36.4 Signal Description
| Signal Name | Type | Description |
|---|---|---|
| PAD[0] | Digital I/O | SDA |
| PAD[1] | Digital I/O | SCL |
| PAD[2] | Digital I/O | SDA_OUT (4-wire operation) |
| PAD[3] | Digital I/O | SCL_OUT (4-wire operation) |
CAUTION: When the SERCOM is used in
I2C mode, the SERCOM controls the direction and value of the I/O pins.
The PORT Control bit (PINCFGn.DRVSTR) is still effective for the SERCOM output pins. The PORT Control bit (PINCFGn.PULLEN) is still effective on the SERCOM input pins, but is limited to the enabling or disabling of a pull down only (it is not possible to enable or disable a pull up). If the receiver or transmitter is disabled, these pins can be used for other purposes.
Important: I²C is not supported on
all SERCOM pins.
The following table lists the SERCOM pins which support I2C:
| Pin Name | Peripheral C SERCOM | Peripheral D SERCOM ALT |
|---|---|---|
| PA08 | SERCOM1/PAD[0] | SERCOM2/PAD[0] |
| PA09 | SERCOM1/PAD[1] | SERCOM2/PAD[1] |
| PA12 | SERCOM2/PAD[0] | SERCOM4/PAD[0] |
| PA13 | SERCOM2/PAD[1] | SERCOM4/PAD[1] |
| PA16 | SERCOM1/PAD[0] | SERCOM0/PAD[0] |
| PA17 | SERCOM1/PAD[1] | SERCOM0/PAD[1] |
| PA22 | SERCOM0/PAD[0] | SERCOM2/PAD[0] |
| PA23 | SERCOM0/PAD[1] | SERCOM2/PAD[1] |
| PB12 | SERCOM3/PAD[0] | - |
| PB13 | SERCOM3/PAD[1] | - |
| PB16 | SERCOM5/PAD[0] | - |
| PB17 | SERCOM5/PAD[1] | - |
| PB30 | SERCOM1/PAD[0] | SERCOM5/PAD[0] |
| PB31 | SERCOM1/PAD[1] | SERCOM5/PAD[1] |
CAUTION:
- I2C is not supported on SERCOM3 and SERCOM5 for 48-pin packages. Refer to the Pinout for additional information.
- I/Os for SERCOM peripherals are grouped into I/O sets, listed in their ‘IOSET’ column in the pinout tables. For these peripherals, it is mandatory to use I/Os that belong to the same I/O set. The timings are not guaranteed when I/Os from different I/O sets are mixed. Refer to the Pinout and Packaging chapter to get IOSET definitions.
| Pin Name | Peripheral C SERCOM | Peripheral D SERCOM ALT |
|---|---|---|
| PA08 | SERCOM1/PAD[0] | SERCOM2/PAD[0] |
| PA09 | SERCOM1/PAD[1] | SERCOM2/PAD[1] |
| PA16 | SERCOM1/PAD[0] | SERCOM0/PAD[0] |
| PA17 | SERCOM1/PAD[1] | SERCOM0/PAD[1] |
| PA22 | SERCOM0/PAD[0] | SERCOM2/PAD[0] |
| PA23 | SERCOM0/PAD[1] | SERCOM2/PAD[1] |
CAUTION:
- I/Os for SERCOM peripherals are grouped into I/O sets, listed in their ‘IOSET’ column in the pinout tables. For these peripherals, it is mandatory to use I/Os that belong to the same I/O set. The timings are not guaranteed when I/Os from different I/O sets are mixed. Refer to the Pinout and Packaging chapter to get IOSET definitions.