SAM4L Datasheet, PDF (699/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
27. Two-wire Master Interface (TWIM)
Rev: 1.2.0.1
27.1 Features
• Compatible with I²C standard
– Multi-master support
– Transfer speeds up to 3.4 Mbit/s
– 7- and 10-bit and General Call addressing
• Compatible with SMBus standard
– Hardware Packet Error Checking (CRC) generation and verification with ACK control
– 25 ms clock low timeout delay
– 10 ms master cumulative clock low extend time
– 25 ms slave cumulative clock low extend time
• Compatible with PMBus
• Compatible with Atmel Two-wire Interface Serial Memories
• DMA interface for reducing CPU load
• Arbitrary transfer lengths, including 0 data bytes
• Optional clock stretching if transmit or receive buffers not ready for data transfer
27.2 Overview
The Atmel Two-wire Master Interface (TWIM) interconnects components on a unique two-wire
bus, made up of one clock line and one data line with speeds of up to 3.4 Mbit/s, 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 a real time clock (RTC), dot matrix/graphic LCD
controller, and temperature sensor, to name a few. The TWIM is always a bus master and can
transfer sequential or single bytes. Multiple master capability is supported. Arbitration of the bus
is performed internally and relinquishes the bus 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.Table 27-1 lists the compatibility level of the Atmel Two-wire Interface in
Master Mode and a full I²C compatible device.
Table 27-1. Atmel TWIM Compatibility with I²C Standard
I²C Standard
Atmel TWIM
Standard-mode (100 kbit/s)
Supported
Fast-mode (400 kbit/s)
Supported
Fast-mode Plus (1 Mbit/s)
Supported
High-speed-mode (3.4 Mbit/s)
Supported
7- or 10-bits Slave Addressing
START BYTE⁽¹⁾
Supported
Not Supported
Repeated Start (Sr) Condition
Supported
ACK and NACK Management
Supported
Slope Control and Input Filtering (Fast mode)
Supported
Clock Stretching
Supported
Note: 1. START + b000000001 + Ack + Sr
42023C–SAM–02/2013
699