Hardware I2C fail on ESP32_C3 - timing value error

[haybarry]

Hardware I2C fails on ESP32_C3 with i2c timing value error.

i2c=I2C(0, scl=Pin(5), sda=Pin(4))

fails with error
E (87717) i2c: i2c_set_timeout(783): i2c timing value error.

Hardware: Lilygo T-OI Plus V1.0 ESP32-C3 (revision 3)

SoftI2C instantiates, but I2C does not recognise stop condition

Micropython:
Version v1.17-20-g0a5107372
Compiled on RPi 4 with idf4.3

Same MicroPython compiled for ESP32 or ESP32_S2 successfully instantiates i2c

--Barry

[fivdi]

This error also occurs with MicroPython v1.18 on a LILYGO T-01C3. Here is an example of the error occuring in the REPL:

MPY: soft reboot
MicroPython v1.18 on 2022-01-17; ESP32C3 module with ESP32C3
Type "help()" for more information.
>>> from machine import Pin, I2C
>>> i2c = I2C(0, scl=Pin(8), sda=Pin(2), freq=800000)
E (45966) i2c: i2c_set_timeout(817): i2c timing value error
>>> i2c.scan()
[24]
>>> 

As can be seen, the error message E (45966) i2c: i2c_set_timeout(817): i2c timing value error is printed when creating i2c. However, I2C methods like scan, writeto and readfrom still function as expected.

The following call to i2c_set_timeout causes the error:

micropython/ports/esp32/machine_i2c.c

Line 74 in da4b38e

i2c_set_timeout(self->port, I2C_APB_CLK_FREQ / 1000000 * timeout_us);

The function prototype for i2c_set_timeout is identical for all the different ESP32 cores (ESP32, ESP32C3, ...) and is defined like this:

esp_err_t i2c_set_timeout(i2c_port_t i2c_num, int timeout);

However, the semantics of the timeout parameter varies from core type to core type.

On an ESP32, timeout represents the number of APB clock cycles that need to occur before the timeout expires. The timeout value passed is stored in the lower 20 bits of register I2C_TO_REG.

On an ESP32C3, the number of APB clock cycles that need to occur before the timeout expires is 2 ** timeout. The timeout value passed is stored in the lower 5 bits of register I2C_TO_REG.

[sugarpines]

This caused me issues because the clock was running too fast for my target. I found setting freq=50000 configured I2C with a frequency of 100000 which was a satisfactory work around until addressed.

[RetiredWizard]

I've encountered this error on the ESP32-S3-DevKitC-1 as well:

MicroPython v1.18 on 2022-05-17; ESP32S3 module (spiram) with ESP32S3
Type "help()" for more information.
>>>
>>> from machine import Pin, I2C
>>> i2c = I2C(0,scl=Pin(7),sda=Pin(6))
E (1405330) i2c: i2c_set_timeout(817): i2c timing value error
>>> i2c.scan()
[38, 39]
>>>

[dhalbert]

There are various reported issues with ESP32-S3 and ESP32-C3 in esp-idf. Some have been fixed, but only just recently, and some fixes are not yet in a release. For instance, we (CircuitPython) are seeing problems with at least one sensor that's using clock stretching on S3: espressif/esp-idf#8894.

[dpgeorge]

Until this is fixed, you can use machine.SoftI2C instead of the hardware I2C implementation.

[puppet13th]

Until this is fixed, you can use machine.SoftI2C instead of the hardware I2C implementation.

I have the opposite experience.
on fresh boot, softI2C does not detect any i2c peripheral when i2c.scan() issued
after hardware I2C initialize,softI2C can detect i2c peripheral
example code:

from machine import Pin, SoftI2C,I2C
scl = 18
sda = 19

i2c = SoftI2C(scl=Pin(scl),sda=Pin(sda),freq=20_000)
print(f"softI2C : {i2c.scan()}")

i2c = I2C(0,scl=Pin(scl),sda=Pin(sda),freq=20_000)
print(f"I2C(0) : {i2c.scan()}")

output:

Build:Feb  7 2021
rst:0x1 (POWERON),boot:0xd (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
load:0x3fcd6100,len:0xe3c
load:0x403ce000,len:0x6f4
load:0x403d0000,len:0x28d8
entry 0x403ce000
MicroPython v1.19.1 on 2022-07-05; ESP32C3 module with ESP32C3
Type "help()" for more information.
>>> %Run -c $EDITOR_CONTENT
softI2C : []
I2C(0) : [80]
>>> %Run -c $EDITOR_CONTENT
softI2C : [80]
I2C(0) : [80]

fyi : tested on Lilygo T-OI Plus V1.2 board

[mgsb]

I believe I have figured out the issue. See this PR: #9434

[dpgeorge]

Should be fixed by 12f9948

[alprshn]

bro try it. I solved problem
SSD1306Wire display(0x3c, I2C_SDA, I2C_SCL, GEOMETRY_128_64, I2C_ONE, -1);
You can look this link https://github.com/ThingPulse/esp8266-oled-ssd1306