AT89S8252 View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT89S8252

8 bit Microcontroller with 8K bytes Flash

Atmel Corporation 

Programmable Clock Out

UART

A 50% duty cycle clock can be programmed to come out

on P1.0, as shown in Figure 5. This pin, besides being a

regular I/0 pin, has two alternate functions. It can be pro-

grammed to input the external clock for Timer/Counter 2 or

to output a 50% duty cycle clock ranging from 61 Hz to 4

The UART in the AT89S8252 operates the same way as

the UART in the AT89C51, AT89C52 and AT89C55. For

further information, see the October 1995 Microcontroller

Data Book, page 2-49, section titled, "Serial Interface."

MHz at a 16 MHz operating frequency.

To configure the Timer/Counter 2 as a clock generator, bit

C/T2 ( T 2 C O N . 1 ) m u s t b e c l e a r e d a n d b i t T2 O E

(T2MOD.1) must be set. Bit TR2 (T2CON.2) starts and

stops the timer.

The clock-out frequency depends on the oscillator fre-

quency and the reload value of Timer 2 capture registers

(RCAP2H, RCAP2L), as shown in the following equation.

Serial Peripheral Interface

The serial peripheral interface (SPI) allows high-speed

synchronous data transfer between the AT89S8252 and

peripheral devices or between several AT89S8252 de-

vices. The AT89S8252 SPI features include the following:

• Full-Duplex, 3-Wire Synchronous Data Transfer

• Master or Slave Operation

Clock−Out Frequency =

Oscillator Frequency

4 x [65536 − (RCAP2H, RCAP2L)]

•

•

6 MHz Bit Frequency (max.)

LSB First or MSB First Data Transfer

In the clock-out mode, Timer 2 roll-overs will not generate

an interrupt. This behavior is similar to when Timer 2 is

used as a baud-rate generator. It is possible to use Timer

2 as a baud-rate generator and a clock generator simulta-

• Four Programmable Bit Rates

• End of Transmission Interrupt Flag

• Write Collision Flag Protection

• Wakeup from Idle Mode (Slave Mode Only)

neously. Note, however, that the baud-rate and clock-out

frequencies cannot be determined independently from

(continued)

one another since they both use RCAP2H and RCAP2L.

Figure 6. SPI Block Diagram

14

AT89S8252

Share Link: