Datasheet

AT89C51RB2/RC2

4180E–8051–10/06

PCA Capture Mode To use one of the PCA Modules in the capture mode either one or both of the CCAPM

bits CAPN and CAPP for that Module must be set. The external CEX input for the Mod-

ule (on port 1) is sampled for a transition. When a valid transition occurs the PCA

hardware loads the value of the PCA counter registers (CH and CL) into the Module's

capture registers (CCAPnL and CCAPnH). If the CCFn bit for the Module in the CCON

SFR and the ECCFn bit in the CCAPMn SFR are set then an interrupt will be generated

(see Figure 13).

Figure 13. PCA Capture Mode

CF CR

CCON

0xD8

CH CL

CCAPnH CCAPnL

CCF4 CCF3 CCF2 CCF1 CCF0

PCA IT

PCA Counter/Timer

ECOMn

CCAPMn, n = 0 to 4

0xDA to 0xDE

CAPNn MATn TOGn PWMn ECCFnCAPPn

Cex. n

Capture