11.1.1 Interfacing in I²C/TWI Mode

Twelve Flexible Serial Communication Controller (FLEXCOM) interfaces configurable in Two-Wire Interface (TWI) mode are available on the SAM9X75 SOM Series.

The TWI can interconnect with external components on a unique two-wire bus, made up of one clock line and one data line with speeds of up to 400 Kbits/s in Fast mode and up to 3.4 Mbits/s in High-Speed Client mode only, based on a byte-oriented transfer format.

It can be used with any Two-Wire Interface bus Serial EEPROM and I²C-compatible devices, such as a Real-Time Clock (RTC), a dot matrix/graphic LCD controller or a temperature sensor. The TWI is programmable as a host or a client with sequential or single-byte access. Multiple host capability is supported.

Table 11-1. I²C/TWI Interface Configurations
Interface InstanceIO SetPin No.PIOPin NameComment
FLEXCOM01138PA30FLEXCOM0_IO0External pull-up needed in case the FLEXCOM interface is used as an I²C/TWI interface.
136PA31FLEXCOM0_IO1
FLEXCOM11139PA28FLEXCOM1_IO0
141PA29FLEXCOM1_IO1
FLEXCOM21165PA13FLEXCOM2_IO0
164PA14FLEXCOM2_IO1
FLEXCOM3166PC22FLEXCOM3_IO0
51PC23FLEXCOM3_IO1
FLEXCOM41, 212PA10FLEXCOM4_IO0
13PA9FLEXCOM4_IO1
FLEXCOM51, 2160PA16FLEXCOM5_IO0
162PA15FLEXCOM5_IO1
FLEXCOM61158PA24FLEXCOM6_IO0No external pull-up needed. Already integrated in the SOM.
157PA25FLEXCOM6_IO1
FLEXCOM7159PC0FLEXCOM7_IO0External pull-up needed in case the FLEXCOM interface is used as an I²C/TWI interface.
62PC1FLEXCOM7_IO1
FLEXCOM9155PC8FLEXCOM9_IO0
64PC9FLEXCOM9_IO1
FLEXCOM10173PC16FLEXCOM10_IO0
57PC17FLEXCOM10_IO1
FLEXCOM11123PB15FLEXCOM11_IO0
25PB16FLEXCOM11_IO1
FLEXCOM12126PB17FLEXCOM12_IO0
27PB18FLEXCOM12_IO1