I2C BUS ERROR:noisy bus/unexpected

Hi @jyijyi

MCU Firmware is missing in one of the device under test running on R16 Firmware attached the logs for your reference . Can we know the root cause of this issue ? Are there any limitations in the i2c bus ? when it comes to i2c we are making use of only ADC’s (via internal-MCU) and have only peripherals like Accelero-Gyro , IO expander . Due to previous experiences we had to stop using the ULPM feature but the i2c bus error is still observed in the module .

[83341.038454] i2c-msm-v2 78b8000.i2c: error timeout on polling for valid state. check core_clk
[83341.048971] i2c-msm-v2 78b8000.i2c: BUS ERROR:noisy bus/unexpected start/stop tag: msgs(n:2 cur:0 tx) bc(rx:1 tx:1) mode:FIFO slv_addr:0x20 MSTR_STS:0x001121c4 OPER:0x00000000
[83341.067161] i2c-msm-v2 78b8000.i2c: error timeout on polling for valid state. check core_clk
[83341.120027] i2c-msm-v2 78b8000.i2c: BUS ERROR:noisy bus/unexpected start/stop tag: msgs(n:2 cur:0 tx) bc(rx:1 tx:1) mode:FIFO slv_addr:0x6a MSTR_STS:0x001121c4 OPER:0x00000000

Let me know if you need any other details .
newLogread (1.9 MB)
DMESG_LOGS.txt (94.4 KB)

Is this happening to one module only?
Is this randomly happening on this module?

We have observed this earlier in old firmware in multiple modules . Now observed in latest fw as well . Yes its happening randomly

This issue should be fixed in r13, can you try it and see if the is regression in r16?

Hi @jyijyi ,
Its difficult to migrate or test the build on R13.1 at this point as we are supposed to deliver devices to customers . According to release note the I2C bus ARB_LOST error under stress test was solved in MCU FW 002.013 and R16 has MCU FW 002.015 . Do you really think this can be regression in R16 ?

I don’t know as this is not happening to my module here.

You better take one to do test

Hi Akshay,

For the error it will be required to verify if the error comes on the multiple devices. Usually it is best to test on the mangOH Hardware platform to rule out the possibility with the Module.

For checking specific Hardware issues verify the issue reproduced on multiple devices. If it is faced on multiple devices you can then try to check which I2C device is causing the issue.