9

AT75C320

1769A–07/01

USART:

Universal

Synchronous/

Asynchronous

Receiver/

Transmitter

The AT75C320 provides two identical full-duplex, universal synchronous/asynchronous

receiver/transmitters that interface to the APB and are connected to the peripheral data

controller.

The main features are:

•

Programmable baud rate generator

•

Parity, framing and overrun error detection

•

Line break generation and detection

•

Automatic echo, local loopback and remote loopback

•

Multi-drop mode: address detection and generation

•

Interrupt generation

•

Dedicated peripheral data controller channels

•

6-, 7-, 8- and 9-bit character length

•

In addition to the Tx and Rx signals, the USART A provides several modem control lines.

SPI: Serial

Peripheral

Interface

The AT75C320 includes an SPI that provides communication with external devices in master

or slave mode.

The SPI has one external chip select that can be connected to two devices. The data length is

programmable from 8- to 16-bit.

Timer/Counter

The AT75C320 features three identical 16-bit timer/counters. They can be independently pro-

grammed to perform a wide range of functions, including frequency measurement, event

counting, interval measurement, pulse generation, delay timing and pulse width modulation.

The triple timer/counter block has three external clock inputs, five internal clock inputs and two

multi-purpose signals that can be configured by the user. Each timer drives an internal inter-

rupt signal that can be programmed to generate processor interrupts via the advanced

interrupt controller.

Watchdog Timer

The AT75C320 has an internal watchdog timer that can be used to prevent system lock-up if

the software becomes trapped in a deadlock.

Special Functions

The AT75C320 provides registers that implement the following special functions:

•

Chip identification

•

Reset status

Application

Software

The AT75C320 is supported by a comprehensive range of software modules. As a result of

the widespread use of the ARM7TDMI and the OakDSPCore, a wide range is available, either

directly from Atmel or from third parties.

The application software modules are in three categories: OS level, DSP level and application

level.

OS Level

The AT75C320 is supplied with a customized port of the Linux kernel. It features device driv-

ers for all the on-chip peripherals, including the DSP subsystems, and supports virtual file

system usage. It also supports the native TCP/IP facilities that have made Linux a success in

Internet applications. This kernel is available in source code under the terms of the Gnu Public

License.

Many other operating systems exist for the ARM7TDMI core.