CubeCell

Project CubeCell
Low-power LoRaWAN Board
Status	In progress
Contact	bertrik
Last Update	2022-03-27

Intro

This page is about the CubeCell board from heltec.org, aka HTCC-AB01

the github page for the Arduino code

What I'd like to investigate:

• Does it have an RTC? YES, it appears so
• --Can we run the arduino-lmic library on this? NO, probably not in the short term--
• --Can we compile the code with platformio? YES--
• Use this board for my LoraBatBox
• Video review by Andreas Spiess

Hardware

Features:

• based on an ASR605x (ARM cortex M0+ core) + SX1262 radio chip
• low power, only microamps sleep current
• battery connection
• solar cell connection
• pinout

According to https://heltec.org/project/htcc-ab01/ this board has only 16 kB RAM, so things might get a bit tight. A basic LoRaWAN "hello world" example with the basicmac stack uses approximately 2336 bytes.

Software

Example code

• A basic working LoRaWAN platformio demo project is available at https://github.com/bertrik/cubecelldemo
• LoraWan example code from Heltec (not recommended)

The CubeCell hardware works with (an export of) the basicmac device stack from Lacuna Space, just needs a pinmap definition, (see also https://www.thethingsnetwork.org/forum/t/heltec-cubecell-part-2/37225/72):

const lmic_pinmap lmic_pins = {
    .nss = RADIO_NSS,
    .tx = LMIC_CONTROLLED_BY_DIO2,
    .rx = LMIC_UNUSED_PIN,
    .rst = RADIO_RESET,
    .dio = {LMIC_UNUSED_PIN, RADIO_DIO_1, LMIC_UNUSED_PIN},
    .busy = RADIO_BUSY,
    .tcxo = LMIC_CONTROLLED_BY_DIO3,
};

Troubleshooting

Failure to initialize hardware

The SPI clock in the basic mac stack is configured by default to 10 MHz. Reducing this to 1 MHz makes it start much more reliably. This can be configured in hal.cpp , change:

 static const SPISettings settings(10E6, MSBFIRST, SPI_MODE0);

into

 static const SPISettings settings(1E6, MSBFIRST, SPI_MODE0);

Timing issues

The stack complains about event being out of order. These can be 'fixed' by configuring DCFG_rxrampup to some high number, e.g. 10000

Still, I'm seeing trouble to have joins succeed in the first try. When it does succeed, it's usually already up to SF11.