12 AT89C5132 4173ES–USB–09/07
Peripherals
The AT8xC5132 peripherals are briefly described in the following sections. For further
details on how to interface (hardware and software) to these peripherals, please refer to
the AT8xC5132 complete datasheet.
Clock Generator System The AT8xC5132 internal clocks are extracted from an on-chip PLL fed by an on-chip
oscillator. Four clocks are generated respectively for the C51 core, the audio interface,
and the other peripherals. The C51 and peripheral clocks are derive d from the oscillator
clock. The audio interface sample rates are also obtained by dividing the PLL output
clock.
Ports The AT8xC5132 implement five 8-bit ports (P0 to P4) and one 4-bit port (P5). In addition
to performing general-purpose I/Os, some ports are capable of external data memory
operations; others allow for alternate functions. All I/O Ports are bidirectional. Each P or t
contains a latch, an output driver and an input buffer. Port 0 and Port 2 output drivers
and input buffers facilitate external memory operations. So me P ort 1 , Port 3 and Por t 4
pins serve for both general-purpose I/Os and alternate functions.
Timers/Counters The AT8xC5132 implement the two general-purpose, 16-bit Timers /Counte rs of a stan -
dard C51. They are identified as Timer 0, Timer 1, and can independently be configured
each to operate in a variety of modes as a Timer or as an event Counter. Whe n op erat -
ing as a Timer, a Timer/Counter runs for a programmed length of time, then issues an
interrupt request. When operating as a Counter, a Timer/Counter counts negative transi -
tions on an external pin. After a preset number of counts, the Counter issues an interrupt
request.
Watchdog Timer The AT8xC5132 implement a hardware Watchdog Timer that automatically resets the
chip if it is allowed to time out. The WDT provides a means of recovering from routi nes
that do not complete successfully due to software or hardware malfu nctions.
Audio Output Interface The AT8xC5132 implements an audio output interface allowing the decoded audio bit-
stream to be output in various formats. They are compatible with right and left
justification PCM and I2S formats and the on-chip PLL allows connection of almost all
commercial audio DAC families available on the market.

Universal Serial Bus

Interface The AT8xC5132 implements a full-speed Universal Serial Bus Interface. The USB inte r-
face can be used for the following purposes:
• Download of files by supporting the USB mass storage class.
• In-System Programming by supporting the USB firmware upgrade class.

MultiMedia Card

Interface The AT8xC5132 implements a MultiMedia Card (MMC) interface compliant to the V2.2
specification in MultiMedia Card mode. The MMC allows storage of files in removable
Flash memory cards that can be easily plugged or removed from the application. It can
also be used for In-System Programming.
IDE/ATAPI Interface The AT8xC5132 provide an IDE/ATAPI interface allowing connec tion of devices such as
CD-ROM reader, CompactFlash™ cards, Hard Disk Drive, etc. It consists of a 16-bit bidi-
rectional bus part of the low-level ANSI ATA/ATAPI specification. It is p rovided for mass
storage interface but could be used for In-System Programming using CD-ROM.