esp32/machine_i2c: Fix default I2C pins for C3, S3.

The default I2C init does not require setting SCL or SDA but the default
I2C0 pins for C3, S3 conflict with the espressif GPIO usage.

For the C3, pins 18/19 are for USB/JTAG.  If used for I2C() they will cause
the REPL to hang on initialization of the I2C.

For the S3 pin 19 is allocated for USB/JTAG also but the defaults do not
seem to affect the REPL.

See related micropython#16956.

Fixes issue micropython#17103.

Signed-off-by: Rick Sorensen <[email protected]>
Signed-off-by: Angus Gratton <[email protected]>

Author: ricksorensen

ports/esp32/machine_i2c.c

@@ -35,9 +35,14 @@
 #if MICROPY_PY_MACHINE_I2C || MICROPY_PY_MACHINE_SOFTI2C
 
 #ifndef MICROPY_HW_I2C0_SCL
+#if CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32S3
+#define MICROPY_HW_I2C0_SCL (GPIO_NUM_9)
+#define MICROPY_HW_I2C0_SDA (GPIO_NUM_8)
+#else
 #define MICROPY_HW_I2C0_SCL (GPIO_NUM_18)
 #define MICROPY_HW_I2C0_SDA (GPIO_NUM_19)
 #endif
+#endif
 
 #ifndef MICROPY_HW_I2C1_SCL
 #if CONFIG_IDF_TARGET_ESP32