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Unformatted text preview: e period between incrementing TMR or WDT. If the prescaler ratio is 1:2, TMR0 (or WDT) value is increased by one when there are two input signals. If the prescaler ratio is 1:4, four input signals are required to increase TMR0 (or WDT) by one. Figure 4.2.4 and 4.2.5 illustrate a simplified scheme of relation between a timer and a prescaler. Figure 4.2.4 Prescaler Ratio 1:2 (Timer : Prescaler) Figure 4.2.5 Prescaler Ratio 1:4 (Timer : Prescaler) 4.2.5
TMR0’s source is an internal clock and thus it is used as a Timer. TMR0’s edge select bit is 0 (rising edge), although it has no meaning when TMR0 is a Timer. Default prescaler ratio is 1:2. When the OPTION register is initialized with 0, its state would be: That is, TMR0 is used as a timer, and the external impulse device becomes obsolete in this case (it might be better to connect it to VSS or VDD). Physically, TMR0 timer is a register whose value is continually increasing to the maximum value of 8-bits, 255 (0FFH), and then it starts all ov...
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This note was uploaded on 11/21/2010 for the course MECHANICAL mae302 taught by Professor Jang during the Spring '10 term at Seoul National.
- Spring '10