AT89C5131-RDTIL datasheet(56/176 Pages) ATMEL

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AT89C5131

4136B–USB–09/03

The CMOD register includes three additional bits associated with the PCA (See

Figure 25 and Table 49).

•

The CIDL bit allows the PCA to stop during idle mode.

•

The WDTE bit enables or disables the watchdog function on module 4.

•

The ECF bit when set causes an interrupt and the PCA overflow flag CF (in the

CCON SFR) to be set when the PCA timer overflows.

The CCON register contains the run control bit for the PCA and the flags for the PCA

timer (CF) and each module (see Table 50).

•

Bit CR (CCON.6) must be set by software to run the PCA. The PCA is shut off by

clearing this bit.

•

Bit CF: The CF bit (CCON.7) is set when the PCA counter overflows and an

interrupt will be generated if the ECF bit in the CMOD register is set. The CF bit can

only be cleared by software.

•

Bits 0 through 4 are the flags for the modules (bit 0 for module 0, bit 1 for module 1,

etc.) and are set by hardware when either a match or a capture occurs. These flags

can only be cleared by software.

Reset Value = 000X 0000b

Not bit addressable

Table 50. CCON Register

CCON - PCA Counter Control Register (D8h)

7654

3210

–

CCF4

CCF3

CCF2

CCF1

CCF0

Bit

Number

Bit

Mnemonic Description

7CF

PCA Counter Overflow flag

Set by hardware when the counter rolls over. CF flags an interrupt if bit ECF in

CMOD is set. CF may be set by either hardware or software but can only be cleared

by software.

6CR

PCA Counter Run control bit

Must be cleared by software to turn the PCA counter off.

Set by software to turn the PCA counter on.

5–

Reserved

The value read from this bit is indeterminate. Do not set this bit.

CCF4

PCA Module 4 interrupt flag

Must be cleared by software.