Hello @clarksn

hmm, this sounds a lot like a polarity issue with the battery cables. Unfortunately there is no standard for this particular battery connector about which pin to be plus and minus. I've seen both variants in the wild.

My M5Tough, powered via internal battery connector, takes about 68 mA @ 4 V when running UIFlow2.

Thanks
Felix

Hello @RubberDuck

I can confirm the shark fin like signals on my M5CoreS3. I am no I2C expert, but I think they might be marginal and so maybe just barely working on one M5CoreS3 but not on the other when talking to AXP2101. Maybe a stronger pull-up resistor might help?

BTW: I checked the I2C SCL line on an M5Core2 and it is much more rectangular, e.g. much more like I would expect it.

Thanks
Felix

Hello @RubberDuck

just curious, any particular reason you did not read out register 0x22? It is my understanding that this register determines whether the system powers off or does a reset when writing 0x01 to register 0x10.

Also curious, when the issue happens, is the battery full or close to be fully discharged?

The register values of the bad AXP2101 seem to be random. Have you tried to lower the I2C bus speed?

In my experience seemingly random issues often stem from bad / not sufficient power supply. Is the battery in good shape?

Thanks
Felix

Hello @scroggyg

I modified my test program to use internal I2C, did a i2c scan w/o ExtIO2 connected and with it - there seems to be no i2c address conflict.

For me ExtIO2 works either connected to port A or to internal. What I noticed though is that I need to wait (after powering up M5Tab5) for the UIFlow2 screen fully being loaded before running the program.

If I do not wait long enough I occasionally see a crash too.

Thanks
Felix

Hello @scroggyg

here are the result of my tests with various firmware versions:
v2.3.5 : running program -> crash
v2.3.6 : running program -> crash
v2.3.6 hotfix : running program -> ok
v2.3.6 hotfix2 : running program -> ok

Note:

• I had no issue burning an running any of the above firmware versions.
• I run all my tests with no battery attached.

You can find the program I used in the UIFlow Project Zone: M5Tab5_ExtIO2_Test_UIFlow2.3.6

Thanks
Felix

Hello @Handcannon

M5Tab5 UIFlow v2.3.6-hotfix solves the no power on port A issue.

Thanks
Felix

Hello @HappyUser

I found an SX1276 LoRa in my box of electronics and wired it up to an M5Core2 using the same GPIOs as the LoRa module is using.

Then I tested with the stock LoRaReceiver example (adapted to M5Core2) and with some added output to the display successfully. E.g. both LoRa and display worked fine together. You can find my example here.

What do you mean by restart? Powering up M5Core2 or pressing the reset button or after uploading new firmware?

How are you powering the M5Core2? Maybe there is a power supply issue?

Thanks
Felix

Hello @HappyUser

you do not need to explicitly call M5.Power.begin() as it is already called from within M5.begin().

Well, as soon as you call M5.Display.startWrite() it will assert the display CS line and occupy the SPI bus for the display until you call M5.Display.endWrite(). In other words, between those two calls the SPI bus can only be used for display updates.

Question: why are you calling M5.Display.startWrite() explicitly at all? You should be able to write onto the display by calling M5.Display.println() or similar without first calling M5.Display.startWrite(). Doesn't that work for you?

Thanks
Felix

Hello @HappyUser

I think you are missing the M5.begin() in setup(). Without that call, the 5 V isn't turned on, e.g. the LoRa module is not powered. (At least on my M5Core2 5 V is not present without the M5.begin() call.)

And I think the RST_PIN should be GPIO 26 (as it hasn't changed from M5Core to M5Core2).

Note: I do not have this LoRa module so I cannot test myself.

Thanks
Felix

Hello @eleonorafontana16

just to clarify - your current setup (controlling 2 servos using GPIO25 and GPIO26) doesn't include the GoPlus2 module anymore, correct?

Thanks
Felix