Rainbow-electronics T89C51CC02 Manual do Utilizador descarregar pdf (Página 105)

Rev.A - May 17, 2001 105

Preliminary

T89C51CC02

16.3. PCA Capture Mode

To use one of the PCA modules in 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 module (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.

Figure 106. PCA Capture Mode

CEXn

n = 0, 1

PCA Counter

(8bits)

CCAPnH

CCAPnL

CCFn

CCON Reg

PCA

Interrupt

Request

- 0CAPPnCAPNn000 ECCFn

CCAPMn Register (n = 0, 1)

1 2 ... 100 101 102 103 104 105 106 107 108 109 110 ... 136 137

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