<![CDATA[[CoreS3] I2C doesn't work...]]>Hi!

I can't get I2C working properly with my CoreS3...

Environment:

  • CoreS3
  • ENV-III sensor on Port A or Port B (no difference)
  • Arduino IDE 2.2.1 with M5CoreS3 0.0.4
  • Same with PlatformIO Core 6.1.11 with M5CoreS3 0.0.4

The issue is really weird:

  1. Connect a sensor on Port A or B
  2. Flash the "CoreS3 UserDemo" with M5Burner. Sensor can be seen in the I2C menu
  3. Flash a program using I2C (E.g. the I2C_Tester.ino from the sample folder)
  4. So far so good, it all works, we can get data from the SHT30 and the QMP6988 without any issue. Works on Port A and Port B.
  5. Power off the device completely (Battery off, USB cable disconnected), the re-connect.
  6. I2C doesn't work anymore (behavior is slightly different with the port: Port A times out and Port B just doesn't see any sensor, but none work)
  7. The only way to get I2C back is to re-flash "CoreS3 UserDemo"

I2C does work as expected with UiFlow, so I assume the CoreS3 and the ENV-III aren't faulty.
I would think that I2C isn't properly initialized at startup...

The PIO console sometimes shows memory allocation error during startup (before setup() is invoked)

0:40:11.059 > ESP-ROM:esp32s3-20210327
20:40:11.059 > Build:Mar 27 2021
20:40:11.060 > rst:0xc (RTC_SW_CPU_RST),boot:0x2b (SPI_FAST_FLASH_BOOT)
20:40:11.060 > Saved PC:0x40377900
20:40:11.062 > SPIWP:0xee
20:40:11.062 > mode:DIO, clock div:1
20:40:11.064 > load:0x3fce3808,len:0x44c
20:40:11.066 > load:0x403c9700,len:0xbe4
20:40:11.068 > load:0x403cc700,len:0x2a68
20:40:11.090 > entry 0x403c98d4
20:40:11.245 > [   186][E][Wire.cpp:152] allocateWireBuffer(): Can't allocate memory for I2C_0 rxBuffer
20:40:11.247 > [   187][I][esp32-hal-i2c.c:75] i2cInit(): Initialising I2C Master: sda=2 scl=1 freq=100000
20:40:12.143 > [  1084][I][esp32-hal-psram.c:96] psramInit(): PSRAM enabled
20:40:12.160 > Initialize M5
20:40:13.660 > M5CoreS3 initializing...OK
]]>https://community.m5stack.com/topic/5654/cores3-i2c-doesn-t-workRSS for NodeSun, 19 Apr 2026 00:09:33 GMTTue, 19 Sep 2023 19:02:42 GMT60<![CDATA[Reply to [CoreS3] I2C doesn't work... on Wed, 20 Sep 2023 10:50:41 GMT]]>@felmue That was the problem

Thank you very much!

]]>https://community.m5stack.com/post/22272https://community.m5stack.com/post/22272Wed, 20 Sep 2023 10:50:41 GMT<![CDATA[Reply to [CoreS3] I2C doesn't work... on Wed, 20 Sep 2023 08:12:43 GMT]]>@felmue there is also a king running issue with the ENV III unit

]]>https://community.m5stack.com/post/22269https://community.m5stack.com/post/22269Wed, 20 Sep 2023 08:12:43 GMT<![CDATA[Reply to [CoreS3] I2C doesn't work... on Wed, 20 Sep 2023 08:10:22 GMT]]>Hello @Amedee

on M5CoreS3 the 5 V on the Groove ports needs to be enabled explicitly. See section Power Management here.

Try calling below function in setup():

M5.Axp.powerModeSet(POWER_MODE_USB_IN_BUS_OUT);

Thanks
Felix

]]>https://community.m5stack.com/post/22268https://community.m5stack.com/post/22268Wed, 20 Sep 2023 08:10:22 GMT