LoRa32 V4 hardware revision updates

#1

Be aware of the new version v4.3.1.

Noteable changes:

  • The FEM chip has been upgraded to KCT8103L .
  • A filter footprint has been reserved in the RX chain (not populated by default at the factory, allowing for future expansion and debugging).
  • GPIO5 has been reassigned as the FEM control pin, and GPIO46 is now reserved as an available pin.
  • The reverse polarity protection MOSFET has been changed from AO3400 to SI2302.
  • Optimized the power consumption caused by the ADC remaining continuously enabled, reducing overall standby power consumption.
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#2

This would be a firmware issue or an AI hallucination.

Also, still using the ESP32-S3R2 SOC which is EOL.

#3

Have you looked at the schematic?

There seems to have been some reconfiguration of the FEM that ties in with the change in function of GPIO5/GPIO46 (which has me wondering how this may impact existing software that does not use the Heltec libraries, which will presumably handle any changes behind the scenes), but can you work out why theyā€™ve explicitly, and apparently uniquely, configured a pull-down resistor on GPIO46 now?

The change notes state that GPIO46 ā€œis now reserved as an available pinā€, which is a confusing statement in itselfā€”I would have thought that a pin would be EITHER reserved OR availableā€¦ So Iā€™m wondering if Iā€™ve missed something else. I got smacked by the GPIO46 ā€˜reserved pinā€™ status (i.e. NOT available as a generally useable GPIO) on the original board, so Iā€™m just wondering if anything really has changed at a practical level on that frontā€¦

Either way, these seemingly arbitrary changes in pin functions, which have well and truely taken on ā€˜regular eventā€™ status since the original release of the WiFi LoRa 32 board, can really mess with any ongoing effort to incorporate these boards into anything that resembles a stable designā€¦

#4

Wasnā€™t uploaded last night, but have now.

  • The MOSFET hasnā€™t changed.
  • GPIO46 not labelled as PA_CPS - as for the pull-down, as thereā€™s no readily available data sheet, who knows!
  • The KCT8103L appears to have Rx LNA bypass which is good for shorter ranges.
  • We now appear to have two potential footprints on the Rx line for who knows what - maybe a Band Pass Filter before the LNA, not sure what youā€™d want after.
  • Without seeing the PCB itā€™s hard to comment but with the power output, Iā€™d like the network on the output match to allow for a Low Pass Filter.

Still a hot mess, such a shame as the solar input was a useful addition. And with the GNSS module, the MeshX crowd (tastic & Core) could have fun and provide a replacement for the MeshTower!

#5

They revised the update log - two entries discussed here are now formulated differently:

  • The FEM chip has been upgraded to KCT8103L, allowing software control over whether the RX signal path passes through the LNA.

  • A SAW filter pad is now reserved in the RX chain. It is not populated by default, providing flexibility for future expansion, customization, and RF debugging.