SAM7X256_14 Datasheet, PDF (269/662 Pages) ATMEL Corporation – ARM-based Flash MCU

29. Two-wire Interface (TWI)
29.1
Overview
The 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 master
transmitter or master receiver with sequential or single-byte access. A configurable baud rate generator permits the
output data rate to be adapted to a wide range of core clock frequencies. Below, Table 29-1 lists the compatibility level of
the Atmel Two-wire Interface and a full I2C compatible device.
Table 29-1. Atmel TWI compatibility with i2C Standard
I2C Standard
Atmel TWI
Standard Mode Speed (100 KHz)
Supported
Fast Mode Speed (400 KHz)
Supported
7 or 10 bits Slave Addressing
START BYTE⁽¹⁾
Repeated Start (Sr) Condition
Supported
Not Supported
Not Fully Supported⁽²⁾
ACK and NACK Management
Supported
Slope control and input filtering (Fast mode)
Not Supported
Clock strectching
Supported
Notes: 1. START + b000000001 + Ack + Sr
2. A repeated start condition is only supported in Master Receiver mode. See Section 29.5.5 “Internal
Address” on page 274
29.2 Block Diagram
Figure 29-1. Block Diagram
APB Bridge
PMC
MCK
Two-wire
Interface
PIO
TWI
Interrupt
AIC
TWCK
TWD
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
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