TS80C51RA2-VCKB datasheet(32/74 Pages) ATMEL

32 / 74 page

Rev. C - 06 March, 2001

TS80C51RA2/RD2

TS83C51RB2/RC2/RD2

TS87C51RB2/RC2/RD2

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.

Figure 11. PCA High Speed Output Mode

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

match could happen.

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.

CCAPnH

CCAPnL

ECOMn

CCAPMn, n = 0 to 4

0xDA to 0xDE

CAPNn MATn

TOGn PWMn ECCFn

CAPPn

16 bit comparator

Match

CCON

0xD8

CCF4

CCF3

CCF2

CCF1

CCF0

PCA IT

Enable

CEXn

PCA counter/timer

Write to

CCAPnH

Reset

Write to

CCAPnL

TS80C51RA2-VCKB Datasheet(PDF) 32 Page - ATMEL Corporation