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PDA 05 5/30/03 11:35 AM Page 94
•
Set GIE bit.
• Set PEIE bit. PDA Robotics
3. Wait for the required acquisition time.
4. Start conversion:
• Set GO/DONE bit (ADCON0).

5. Wait for A/D conversion to complete, by either:
• Polling for the GO/DONE bit to be cleared (with interrupts
enabled); or
• Waiting for the A/D interrupt.

6. Read A/D result register pair (ADRESH:ADRESL); clear bit ADIF
if required.

7. For the next conversion, go to step 1 or step 2, as required. The
A/D conversion time per bit is defined as TAD. A minimum wait
of 2TAD is required before the next acquisition starts.

Once again, the C compiler we are using in this project takes care of
the preceding steps in a few simple lines of code!

Timer0 Module. The Timer0 module timer/counter has the follow-
ing features:

• 8-bit timer/counter

• Readable and writable

• 8-bit software programmable prescaler
• Internal or external clock select
• Interrupt on overflow from FFh to 00h

• Edge select for external clock

Figure 5.40 is a block diagram of the Timer0 module and the prescaler
shared with the WDT.
Timer mode is selected by clearing bit T0CS (OPTION_REG<5>). In
Timer mode, the Timer0 module will increment every instruction cycle
(without prescaler). If the TMR0 register is written, the increment is

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