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Unformatted text preview: s 0), or via external impulses (when the bit is 1). The first is a timer and the latter is a counter. 1 = external impulses 0 = internal clock RTE (Bit 4; TMR0 Source Edge Select bit) As described above, beside the internal oscillator clock, timer status can also be increased by the external clock on RA4/TOCKI pin. If this option of external clock was selected (i.e., RTS bit is 1), it would be possible to define the edge of a signal (rising or falling), on which timer would increase its value. If RTE bit is 0, it is a rising edge – i.e., TMR0 value is increased when a signal is changed from ‘low’ to ‘high’. On the other hand, RTE bit with its value 1 indicates a falling edge, TMR0 being increased when a signal is changed from ‘high’ to ‘low’. Note again that RTE bit does not exert influence if TMR0 was enabled with an internal oscillator clock (i.e., RTS bit is 0). 1 = falling edge 0 = rising edge PS2, PS1, PS0 (Bit 2, 1, 0; Prescaler Rate Select bit) The low three bits, PS0, PS1, and PS2, set the prescaler ratio - the tim...
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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