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1779ES–ATARM–14-Apr-06

AT91M42800A

interrupt request to the ARM7TDMI. It integrates an 8-level priority controller, and, using the

Auto-vectoring feature, reduces the interrupt latency time.

The Parallel Input/Output Controllers (PIOA, PIOB) controls up to 54 I/O lines. It enables the

user to select specific pins for on-chip peripheral input/output functions, and general-purpose

input/output signal pins. The PIO controllers can be programmed to detect an interrupt on a sig-

nal change from each line.

There are three embedded system timers. The Real-time Timer (RTT) counts elapsed seconds

and can generate periodic or programmed interrupts. The Period Interval Timer (PIT) can be

used as a user-programmable time-base, and can generate periodic ticks. The Watchdog (WD)

can be used to prevent system lock-up if the software becomes trapped in a deadlock.

The Special Function (SF) module integrates the Chip ID and the Reset Status registers.

5.2.2

User Peripherals

Two USARTs, independently configurable, enable communication at a high baud rate in syn-

chronous or asynchronous mode. The format includes start, stop and parity bits and up to 9 data

bits. Each USART also features a Time-out and a Time-guard register, facilitating the use of the

two dedicated Peripheral Data Controller (PDC) channels.

The two 3-channel, 16-bit Timer/Counters (TC) are highly-programmable and support capture or

waveform modes. Each TC channel can be programmed to measure or generate different kinds

of waves, and can detect and control two input/output signals. Each TC also has three external

clock signals.

Two independently configurable SPIs provide communication with external devices in master or

slave mode. Each has four external chip selects which can be connected to up to 15 devices.

The data length is programmable, from 8- to 16-bit.

6.

Associated Documentation

Table 6-1.

Associated Documentation

Product

Information

Document Title

AT91M42800A

Internal architecture of processor

ARM/Thumb instruction sets

Embedded in-circuit-emulator

ARM7TDMI (Thumb) Datasheet

External memory interface mapping

Peripheral operations

Peripheral user interfaces

AT91M42800A Datasheet

DC characteristics

Power consumption

Thermal and reliability considerations

AC characteristics

AT91M42800A Electrical Characteristics

Product overview

Ordering information

Packaging information

Soldering profile

AT91M42800A Summary Datasheet (this document)