User manual

4.21. Two-wire Interface (TWI)
The TWI is also known under the expression "I²C-Bus", which is a trademark of Philips and may
therefore not be used by other manufacturers. However, interoperability is guaranteed.
The TWI uses only two lines, namely serial data (SDA) and serial clock (SCL). According to the
standard, the TWI clock rate is limited to 400 kHz in fast mode and 100 kHz in normal mode. On the
SAM9261, however, the baudrate can be fixed to any value between
MCK/6 and
MCK / (255*128*2 + 6) ~= MCK / 64k.
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