Boron LTE-M1 radio unresponsive when sending large data continuously

[keeramis]

Problem

Boron LTE-M1 cell radio becomes unresponsive (by getting stuck at an AT command) after "large" data is sent continuously over muxer data channel

Solution

Whenever we encounter a large packet, we enforce a certain number of milliseconds (set to 250ms) to pass before transmitting anything else on this channel. After we send a "large" packet (of size 512 bytes), we drop messages(bytes) for a certain amount of time defined by largePacketTimeoutMs_ (250ms)

Steps to Test

Example App - 1 - Basic connectivity to cloud since proactively sending describe messages to cloud without waiting for a request from cloud

void setup() {
}

void loop() {
}

Example App - 2 - Sending large data packets to cloud

void setup() {
}

void loop() {
    delay(1000);
    Particle.publish("temperature", "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA", PRIVATE);
}

References

ch53040

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Completeness

• User is totes amazing for contributing!
• Contributor has signed CLA (Info here)
• Problem and Solution clearly stated
• Run unit/integration/application tests on device
• Added documentation
• Added to CHANGELOG.md after merging (add links to docs and issues)

[keeramis]

@avtolstoy Please verify if this is the correct place to set for PLATFORM_BSOM

[avtolstoy]

This is the wrong file to define this.

[avtolstoy]

Let's probably move this to the source file into the anonymous namespace constants.

[avtolstoy]

Do we perhaps want to query the firmware version here as well? I think it should be alright to directly query SaraNcpClient here and perhaps make the timeout come from there as well to avoid using a magic value. So something along the lines of:

#if HAL_PLATFORM_MUXER_MAY_NEED_DELAY_IN_TX
auto timeout = cellularNetworkManager()->ncpClient()->mayNeedTxDelay(); // don't judge the name :)
if (timeout > 0) {
    HAL_Delay_Milliseconds(timeout);
}
#endif // HAL_PLATFORM_MUXER_MAY_NEED_DELAY_IN_TX

[avtolstoy]

This also needs to be defined for B SoM: the #else condition here.