https://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&feed=atom&action=historyRhococo prototype hardware debugging - Revision history2024-03-29T15:44:44ZRevision history for this page on the wikiMediaWiki 1.32.1https://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=28777&oldid=prevMahjongg at 22:14, 7 January 20222022-01-07T22:14:58Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Name=RhoCoCo Prototype hardware debugging</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Name=RhoCoCo Prototype hardware debugging</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> |Picture=</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> |Picture=<ins class="diffchange diffchange-inline">Rhococo concept art.png</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Omschrijving=Almost all new hardware, (exceptions do exist, but are rare) will have some faults in them that must be found and solved, this page handles what I found during this quest. </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Omschrijving=Almost all new hardware, (exceptions do exist, but are rare) will have some faults in them that must be found and solved, this page handles what I found during this quest. </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Status=Initializing</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Status=Initializing</div></td></tr>
</table>Mahjongghttps://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=21702&oldid=prevMahjongg: /* April 16, 2019 solution for raised 3V3 during boot */2019-04-16T23:29:03Z<p><span dir="auto"><span class="autocomment">April 16, 2019 solution for raised 3V3 during boot</span></span></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 23:29, 16 April 2019</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l35" >Line 35:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Worst case there could be about ten of such leaks from the Z80 control and data lines into the 3V3, so I should dimension the limiting resistor so that no more than 1/10th of a mA (100µA) can flow into its protection diode. Given that over these series resistors about 1,7 Volt will then fall (5V minus 3.3V) the resistor should be dimensioned, (at least initially) as R = 1,7V / 0.0001A = 17000 ohm, or 17K. I will try 15K resistors first, with the idea that 10K might also be enough, especially as about 0.6V should fall over the protection diode.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Worst case there could be about ten of such leaks from the Z80 control and data lines into the 3V3, so I should dimension the limiting resistor so that no more than 1/10th of a mA (100µA) can flow into its protection diode. Given that over these series resistors about 1,7 Volt will then fall (5V minus 3.3V) the resistor should be dimensioned, (at least initially) as R = 1,7V / 0.0001A = 17000 ohm, or 17K. I will try 15K resistors first, with the idea that 10K might also be enough, especially as about 0.6V should fall over the protection diode.</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">I tested this solution, and it works nicely.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">I have also started to incorporate the things I found so far in an PCB and schematics update, revision 1.9.</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td></tr>
</table>Mahjongghttps://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=21699&oldid=prevMahjongg: /* April 16, 2019 solution for raised 3V3 during boot */2019-04-16T20:52:29Z<p><span dir="auto"><span class="autocomment">April 16, 2019 solution for raised 3V3 during boot</span></span></p>
<table class="diff diff-contentalign-left" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 20:52, 16 April 2019</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l34" >Line 34:</td>
<td colspan="2" class="diff-lineno">Line 34:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>a 3K3 resistor across the 3V3 supply will do the trick.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>a 3K3 resistor across the 3V3 supply will do the trick.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Worst case there could be about ten of such leaks from the Z80 control and data lines into the 3V3, so I should dimension the limiting resistor so that no more than 1/10th of a mA (100µA) can flow into its protection diode. Given that over these series resistors about 1,7 Volt will fall (5V minus 3.3V) the resistor should be dimensioned, (at least initially) as R = 1,7V / 0.0001A = 17000 ohm, or 17K. I will try 15K resistors first, with the idea that 10K might also be enough, especially as about 0.6V should fall over the protection diode.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Worst case there could be about ten of such leaks from the Z80 control and data lines into the 3V3, so I should dimension the limiting resistor so that no more than 1/10th of a mA (100µA) can flow into its protection diode. Given that over these series resistors about 1,7 Volt will <ins class="diffchange diffchange-inline">then </ins>fall (5V minus 3.3V) the resistor should be dimensioned, (at least initially) as R = 1,7V / 0.0001A = 17000 ohm, or 17K. I will try 15K resistors first, with the idea that 10K might also be enough, especially as about 0.6V should fall over the protection diode.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td></tr>
</table>Mahjongghttps://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=21698&oldid=prevMahjongg: /* April 16, 2019 solution for raised 3V3 during boot */2019-04-16T20:51:46Z<p><span dir="auto"><span class="autocomment">April 16, 2019 solution for raised 3V3 during boot</span></span></p>
<table class="diff diff-contentalign-left" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 20:51, 16 April 2019</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l31" >Line 31:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== April 16, 2019 solution for raised 3V3 during boot ==</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>== April 16, 2019 solution for raised 3V3 during boot ==</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>I noticed the current draw from the propeller, the serial EEPROM, and the I2C I/O expander,the three 3V3 powered devices <del class="diffchange diffchange-inline">that </del>all <del class="diffchange diffchange-inline">are </del>inactive at first boot draw -very- low current if the propeller doesn't start up, <del class="diffchange diffchange-inline">meaning </del>the tiny bit of current that flows from Z80 control signals into the propellers GPIO protection diodes and then into the 3V3 supply has no path to flow away, so it raises up the 3V3 supply level to an unacceptable 3V9. To prevent this I have decided to passively load the 3V3 supply with 1mA<del class="diffchange diffchange-inline">, </del>I chose 1mA, as its a hundredth of the expected current draw, so negligible.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>I noticed <ins class="diffchange diffchange-inline">that </ins>the current draw from the propeller, the serial EEPROM, and the I2C I/O expander, <ins class="diffchange diffchange-inline">(</ins>the three 3V3 powered devices <ins class="diffchange diffchange-inline">, which are </ins>all inactive at first boot<ins class="diffchange diffchange-inline">) </ins>draw -very- low current<ins class="diffchange diffchange-inline">, so </ins>if the propeller doesn't start up, the tiny bit of current that flows from Z80 control signals into the propellers GPIO protection diodes and then into the 3V3 supply has no path to flow away, so it raises up the 3V3 supply level to an unacceptable 3V9. To prevent this I have decided to passively load the 3V3 supply with 1mA<ins class="diffchange diffchange-inline">. </ins>I chose 1mA, as its a hundredth of the expected current draw, so negligible.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>a 3K3 resistor across the 3V3 supply will do the trick.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>a 3K3 resistor across the 3V3 supply will do the trick.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Worst case there could be about ten of such leaks <del class="diffchange diffchange-inline">into </del>the <del class="diffchange diffchange-inline">3V3, from </del>control and data <del class="diffchange diffchange-inline">signals</del>, so I should dimension the limiting resistor <del class="diffchange diffchange-inline">to </del>that no more than 1/10th of a mA (100µA) can flow into its protection diode. Given that over <del class="diffchange diffchange-inline">such a resistor </del>about 1,7 Volt will fall (5V minus 3.3V) the resistor should be dimensioned, (at least initially) as R = 1,7V / 0.0001A = 17000 ohm, or 17K. I will try 15K resistors first, with the idea that 10K might also be enough, especially as about 0.6V <del class="diffchange diffchange-inline">might </del>fall over the protection diode.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Worst case there could be about ten of such leaks <ins class="diffchange diffchange-inline">from </ins>the <ins class="diffchange diffchange-inline">Z80 </ins>control and data <ins class="diffchange diffchange-inline">lines into the 3V3</ins>, so I should dimension the limiting resistor <ins class="diffchange diffchange-inline">so </ins>that no more than 1/10th of a mA (100µA) can flow into its protection diode. Given that over <ins class="diffchange diffchange-inline">these series resistors </ins>about 1,7 Volt will fall (5V minus 3.3V) the resistor should be dimensioned, (at least initially) as R = 1,7V / 0.0001A = 17000 ohm, or 17K. I will try 15K resistors first, with the idea that 10K might also be enough, especially as about 0.6V <ins class="diffchange diffchange-inline">should </ins>fall over the protection diode.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td></tr>
</table>Mahjongghttps://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=21697&oldid=prevMahjongg at 20:47, 16 April 20192019-04-16T20:47:34Z<p></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 20:47, 16 April 2019</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>I looked up the quiescence current of all the 3V3 powered devices, and came to the conclusion that its in the order of a few dozen µA, so that is the main reason that this problem exists, it will probably be enough to statically load the 3V3 supply by a few mA, for this phenomenon to disappear. </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>I looked up the quiescence current of all the 3V3 powered devices, and came to the conclusion that its in the order of a few dozen µA, so that is the main reason that this problem exists, it will probably be enough to statically load the 3V3 supply by a few mA, for this phenomenon to disappear. </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">== April 16, 2019 solution for raised 3V3 during boot ==</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">I noticed the current draw from the propeller, the serial EEPROM, and the I2C I/O expander,the three 3V3 powered devices that all are inactive at first boot draw -very- low current if the propeller doesn't start up, meaning the tiny bit of current that flows from Z80 control signals into the propellers GPIO protection diodes and then into the 3V3 supply has no path to flow away, so it raises up the 3V3 supply level to an unacceptable 3V9. To prevent this I have decided to passively load the 3V3 supply with 1mA, I chose 1mA, as its a hundredth of the expected current draw, so negligible.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">a 3K3 resistor across the 3V3 supply will do the trick.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Worst case there could be about ten of such leaks into the 3V3, from control and data signals, so I should dimension the limiting resistor to that no more than 1/10th of a mA (100µA) can flow into its protection diode. Given that over such a resistor about 1,7 Volt will fall (5V minus 3.3V) the resistor should be dimensioned, (at least initially) as R = 1,7V / 0.0001A = 17000 ohm, or 17K. I will try 15K resistors first, with the idea that 10K might also be enough, especially as about 0.6V might fall over the protection diode.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td></tr>
</table>Mahjongghttps://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=21644&oldid=prevMahjongg: /* April 10, 2019 First bug finds */2019-04-11T12:48:48Z<p><span dir="auto"><span class="autocomment">April 10, 2019 First bug finds</span></span></p>
<table class="diff diff-contentalign-left" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 12:48, 11 April 2019</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l26" >Line 26:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>One possible solution to the problem of too high voltages on 3V3 line is to mount a 3V6 2% zener across the 3V3 supply, I have looked at the datasheet of a 3V6 zener, and it seems possible to do this. I acquired a 3V6 Zener, and will try. If I can get the 3V3 supply line under control, I can use lower value series resistors, which is better when trying to drive the SRAM through them.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>One possible solution to the problem of too high voltages on 3V3 line is to mount a 3V6 2% zener across the 3V3 supply, I have looked at the datasheet of a 3V6 zener, and it seems possible to do this. I acquired a 3V6 Zener, and will try. If I can get the 3V3 supply line under control, I can use lower value series resistors, which is better when trying to drive the SRAM through them.</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">I looked up the quiescence current of all the 3V3 powered devices, and came to the conclusion that its in the order of a few dozen µA, so that is the main reason that this problem exists, it will probably be enough to statically load the 3V3 supply by a few mA, for this phenomenon to disappear. </ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td></tr>
</table>Mahjongghttps://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=21643&oldid=prevMahjongg: /* April 10, 2019 First bug finds */2019-04-11T12:33:23Z<p><span dir="auto"><span class="autocomment">April 10, 2019 First bug finds</span></span></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 12:33, 11 April 2019</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l16" >Line 16:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>a more difficult problem to solve is that I measured 3.9V across the 3V3 supply!</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>a more difficult problem to solve is that I measured 3.9V across the 3V3 supply!</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>somehow the 3V3 is pushed up, <del class="diffchange diffchange-inline">but </del>I had expected it <del class="diffchange diffchange-inline">to</del>! the reason is that 5V signals from the Z80 end up on inputs of the Propeller chip through the current limiting 1K resistors in the data-lines, and the Z80 control output signals /RD /WR and /IORQ, <del class="diffchange diffchange-inline">unfortunately </del>I also found the first real mistake, in that I forgot to insert a limiting resistor in /IORQ, but moved it to the /BUSACK signal where it isn't really needed.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>somehow the 3V3 is pushed up, <ins class="diffchange diffchange-inline">(meaning somehow more current from a higher voltage flows into the 3V3 supply line, than is dissipated from the 3V3 line, and ass the 3V3 regulator can only source current, not sink current the voltage rises above the value the 3V3 regulator tries to regulate to) </ins>I had expected <ins class="diffchange diffchange-inline">that there would be a current flow into the 3V3 supply through protection diodes in the propeller chip, but not that the 3V3 supply would rise beacuse of </ins>it! the reason is that 5V signals from the Z80 end up on inputs of the Propeller chip through the current limiting 1K resistors in the data-lines, and the Z80 control output signals /RD /WR and /IORQ<ins class="diffchange diffchange-inline">. unfortunately while investigating this</ins>, I also found the first real <ins class="diffchange diffchange-inline">layout </ins>mistake <ins class="diffchange diffchange-inline">I made</ins>, in that I forgot to insert a limiting resistor in /IORQ, but moved it to the /BUSACK signal where it isn't really needed. <ins class="diffchange diffchange-inline">This will necessitate a patch!</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>So I have to find a solution for <del class="diffchange diffchange-inline">that</del>, either <del class="diffchange diffchange-inline">drawing </del>current from the 3V3, or increasing the resistance of the series resistors, or both.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>So I have to find a solution for <ins class="diffchange diffchange-inline">too much current flowing into the 3V3 supply</ins>, either <ins class="diffchange diffchange-inline">loading more </ins>current from the 3V3, or increasing the resistance of the series resistors, or both.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Its <del class="diffchange diffchange-inline">possible </del>that when the propeller is started, it will draw more current. Presently the whole board draws just 60 or so mA from the 5V supply! I expect <del class="diffchange diffchange-inline">that </del>to rise to a few hundred mA <del class="diffchange diffchange-inline">when both </del>the <del class="diffchange diffchange-inline">Z80 and </del>propeller <del class="diffchange diffchange-inline">are </del>working, still I have to do something about that 3,9V on the 3V3 supply, the resistors are now dimensioned to limit the current flowing into a propeller pin to no more than 1mA, I suspect that is much to much, but which resistor value is needed can really only be determined experimentally, I regret not remembering during build up to make these resistors easily replaceable as I had planned.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Its <ins class="diffchange diffchange-inline">true </ins>that when the propeller is started, it will draw more current. Presently the whole board draws just 60 or so mA from the 5V supply<ins class="diffchange diffchange-inline">, of which perhaps only a few mA or so is drawn by the 3V3 regulator (I could check that by removing all 5V powered chips, and then measuring the consumption again) </ins>! I expect <ins class="diffchange diffchange-inline">the 3V3 consumption </ins>to rise to a few hundred mA the propeller <ins class="diffchange diffchange-inline">starts </ins>working, still I have to do something about that 3,9V on the 3V3 supply, the resistors are now dimensioned to limit the current flowing into a propeller pin to no more than 1mA, I suspect that is much to much, but which resistor value is needed can really only be determined experimentally, I regret not remembering during build up to make these resistors easily replaceable as I had planned.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For R30 to R37 (data signals) and for R25, R26 and R27, I also plan to remove these resistors, and use round female socket pins instead, so that I can quickly replace these resistors with different values. However, a first attempt to remove the resistors failed, its hard to do without specialized equipment, for example I have to get better solder wick, and so I choose to take the board to my day-job, where I have better equipment. I cannot afford to damage the PCB when pulling out these resistors.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For R30 to R37 (data signals) and for R25, R26 and R27, I also plan to remove these resistors, and use round female socket pins instead, so that I can quickly replace these resistors with different values. However, a first attempt to remove the resistors failed, its hard to do without specialized equipment, for example I have to get better solder wick, and so I choose to take the board to my day-job, where I have better equipment. I cannot afford to damage the PCB when pulling out these resistors.</div></td></tr>
</table>Mahjongghttps://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=21642&oldid=prevMahjongg at 12:23, 11 April 20192019-04-11T12:23:12Z<p></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 12:23, 11 April 2019</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Name=RhoCoCo Prototype hardware debugging</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Name=RhoCoCo Prototype hardware debugging</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Picture=</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Picture=</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> |Omschrijving=Almost all new hardware, (exceptions do exist, but are rare) will have some faults in them that must be found <del class="diffchange diffchange-inline">an </del>solved, this page handles what I found during this quest. </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> |Omschrijving=Almost all new hardware, (exceptions do exist, but are rare) will have some faults in them that must be found <ins class="diffchange diffchange-inline">and </ins>solved, this page handles what I found during this quest. </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Status=Initializing</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Status=Initializing</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Contact=mahjongg</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Contact=mahjongg</div></td></tr>
</table>Mahjongghttps://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=21639&oldid=prevMahjongg at 18:09, 10 April 20192019-04-10T18:09:37Z<p></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 18:09, 10 April 2019</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For R30 to R37 (data signals) and for R25, R26 and R27, I also plan to remove these resistors, and use round female socket pins instead, so that I can quickly replace these resistors with different values. However, a first attempt to remove the resistors failed, its hard to do without specialized equipment, for example I have to get better solder wick, and so I choose to take the board to my day-job, where I have better equipment. I cannot afford to damage the PCB when pulling out these resistors.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>For R30 to R37 (data signals) and for R25, R26 and R27, I also plan to remove these resistors, and use round female socket pins instead, so that I can quickly replace these resistors with different values. However, a first attempt to remove the resistors failed, its hard to do without specialized equipment, for example I have to get better solder wick, and so I choose to take the board to my day-job, where I have better equipment. I cannot afford to damage the PCB when pulling out these resistors.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">So more about </del>this <del class="diffchange diffchange-inline">problem later.</del></div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Meanwhile I managed to replace the resistors with suitable sockets, as the resistors are placed very close together, I could not use 1/10" strips, but had to use loose contacts, but </ins>this <ins class="diffchange diffchange-inline">"operation" was done under a microscope, and went well </ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>One possible solution to <del class="diffchange diffchange-inline">this </del>problem is to mount a 3V6 2% zener across the 3V3 supply, I have looked at the datasheet of a 3V6 zener, and it seems possible to do this. I acquired a 3V6 Zener, and will try.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>One possible solution to <ins class="diffchange diffchange-inline">the </ins>problem <ins class="diffchange diffchange-inline">of too high voltages on 3V3 line </ins>is to mount a 3V6 2% zener across the 3V3 supply, I have looked at the datasheet of a 3V6 zener, and it seems possible to do this. I acquired a 3V6 Zener, and will try<ins class="diffchange diffchange-inline">. If I can get the 3V3 supply line under control, I can use lower value series resistors, which is better when trying to drive the SRAM through them</ins>.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[category:RhoCoCo]]</div></td></tr>
</table>Mahjongghttps://revspace.nl/index.php?title=Rhococo_prototype_hardware_debugging&diff=21638&oldid=prevPinoaffe at 14:41, 10 April 20192019-04-10T14:41:37Z<p></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 14:41, 10 April 2019</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Omschrijving=Almost all new hardware, (exceptions do exist, but are rare) will have some faults in them that must be found an solved, this page handles what I found during this quest. </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> |Omschrijving=Almost all new hardware, (exceptions do exist, but are rare) will have some faults in them that must be found an solved, this page handles what I found during this quest. </div></td></tr>
</table>Pinoaffe