T89C51RD2-SLTC-L View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

T89C51RD2-SLTC-L

0 to 40 MHz Flash Programmable 8-bit Microcontroller

Atmel Corporation 

T89C51RD2

Write to

CCAPnL Reset

Write to

CCAPnH

1

0

Enable

CF CR

CCON

CCF4 CCF3 CCF2 CCF1 CCF0 0xD8

CCAPnH

CCAPnL

16 bit comparator

Match

PCA IT

CH

CL

PCA counter/timer

RESET *

CCAPMn, n = 0 to 4

ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn

0xDA to 0xDE

CIDL WDTE

CMOD

CPS1 CPS0 ECF

0xD9

* Only for Module 4

Figure 10. PCA Compare Mode and PCA Watchdog Timer

Before enabling ECOM bit, CCAPnL and CCAPnH should be set with a non zero value, otherwise an unwanted

match could happen. Writing to CCAPnH will set the ECOM bit.

Once ECOM set, writing CCAPnL will clear ECOM so that an unwanted match doesn’t occur while modifying

the compare value. Writing to CCAPnH will set ECOM. For this reason, user software should write CCAPnL first,

and then CCAPnH. Of course, the ECOM bit can still be controlled by accessing to CCAPMn register.

6.5.3. High Speed Output Mode

In this mode the CEX output (on port 1) associated with the PCA module will toggle each time a match occurs

between the PCA counter and the module's capture registers. To activate this mode the TOG, MAT, and ECOM

bits in the module's CCAPMn SFR must be set (See Figure 11).

A prior write must be done to CCAPnL and CCAPnH before writing the ECOMn bit.

29

Rev. F - 15 February, 2001

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