C8051F317 View Datasheet(PDF) - Silicon Laboratories

Part Name

Description

Manufacturer

C8051F317

8/16 kB ISP Flash MCU Family

Silicon Laboratories 

C8051F310/1/2/3/4/5/6/7

19.3. PCA Counter

On “REV A” devices, if the main PCA counter (PCA0H : PCA0L) overflows during the execution phase of a

read-modify-write instruction (bit-wise SETB or CLR, ANL, ORL, XRL) that targets the PCA0CN register,

the CF (Counter Overflow) bit will not be set. An example software work-around is as follows:

Step 1. Disable global interrupts (EA = 0).

Step 2. Read PCA0L. This will latch the value of PCA0H.

Step 3. Read PCA0H, saving the value.

Step 4. Execute the bit-wise operation on CCFn (for example, CLR CCF0, or CCF0 = 0;).

Step 5. Read PCA0L.

Step 6. Read PCA0H, saving the value.

Step 7. If the value of PCA0H read in Step 3 is 0xFF and the value for PCA0H read in Step 6 is

0x00, then manually set the CF bit in software (for example, SETB CF, or CF = 1;).

Step 8. Re-enable interrupts (EA = 1).

This behavior is not present on “REV B” and later devices. Software written for “REV A” devices will run on

“REV B” and later devices without modification.

218

Rev. 1.6

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