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RP2040: Remove short-write bitbang from I2C #4378

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Merged
merged 1 commit into from
Mar 26, 2021
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RP2040: Remove short-write bitbang from I2C #4378

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13 changes: 9 additions & 4 deletions ports/raspberrypi/common-hal/busio/I2C.c
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Original file line number Diff line number Diff line change
Expand Up @@ -98,7 +98,12 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
}
#endif

// Create a bitbangio.I2C object to do short writes.
// Create a bitbangio.I2C object to do 0 byte writes.
//
// These are used to non-invasively detect I2C devices by sending
// the address and confirming an ACK.
// They are not supported by the RP2040 hardware.
//
// Must be done before setting up the I2C pins, since they will be
// set up as GPIO by the bitbangio.I2C object.
//
Expand Down Expand Up @@ -157,9 +162,9 @@ void common_hal_busio_i2c_unlock(busio_i2c_obj_t *self) {
}

uint8_t common_hal_busio_i2c_write(busio_i2c_obj_t *self, uint16_t addr,
const uint8_t *data, size_t len, bool transmit_stop_bit) {
if (len <= 2) {
// The RP2040 I2C peripheral will not do writes 2 bytes or less long.
const uint8_t *data, size_t len, bool transmit_stop_bit) {
if (len == 0) {
// The RP2040 I2C peripheral will not perform 0 byte writes.
// So use bitbangio.I2C to do the write.

gpio_set_function(self->scl_pin, GPIO_FUNC_SIO);
Expand Down