Atmel Evaluation Kit AT91SAM9X25-EK AT91SAM9X25-EK Data Sheet
Product codes
AT91SAM9X25-EK
743
SAM9X25 [DATASHEET]
11054E–ATARM–10-Mar-2014
38.
Two-wire Interface (TWI)
38.1 Description
The Atmel Two-wire Interface (TWI) interconnects components on a unique two-wire bus, made up of one clock line and
one data line with speeds of up to 400 Kbits per second, based on a byte-oriented transfer format. It can be used with
any Atmel Two-wire Interface bus Serial EEPROM and I²C compatible device such as Real Time Clock (RTC), Dot
Matrix/Graphic LCD Controllers and Temperature Sensor, to name but a few. The TWI is programmable as a master or a
slave with sequential or single-byte access. Multiple master capability is supported.
one data line with speeds of up to 400 Kbits per second, based on a byte-oriented transfer format. It can be used with
any Atmel Two-wire Interface bus Serial EEPROM and I²C compatible device such as Real Time Clock (RTC), Dot
Matrix/Graphic LCD Controllers and Temperature Sensor, to name but a few. The TWI is programmable as a master or a
slave with sequential or single-byte access. Multiple master capability is supported.
Arbitration of the bus is performed internally and puts the TWI in slave mode automatically if the bus arbitration is lost.
A configurable baud rate generator permits the output data rate to be adapted to a wide range of core clock frequencies.
Below,
lists the compatibility level of the Atmel Two-wire Interface in Master Mode and a full I
2
C compatible
device.
Note:
1. START + b000000001 + Ack + Sr
Table 38-1. Atmel TWI compatibility with I
2
C Standard
I
2
C Standard
Atmel TWI
Standard Mode Speed (100 KHz)
Supported
Fast Mode Speed (400 KHz)
Supported
7 or 10 bits Slave Addressing
Supported
START BYTE
Not Supported
Repeated Start (Sr) Condition
Supported
ACK and NACK Management
Supported
Slope control and input filtering (Fast mode)
Not Supported
Clock stretching
Supported
Multi Master Capability
Supported