M32C80 Datasheet, PDF (161/352 Pages) Renesas Technology Corp – 16/32-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M32C/80 SERIES

M32C/80 Group
14. Timer (Timer A)
14.1.3 One-Shot Timer Mode
In one-shot timer mode, the timer operates only once for each trigger (see Table 14.6). Once a trigger
occurs, the timer starts and continues operating for a desired period. Figure 14.12 shows the TAiMR
register (i=0 to 4) in one-shot timer mode.
Table 14.6 One-Shot Timer Mode Specifications
Item
Count Source
f1, f8, f2n(1), fC32
Specification
Counting Operation
• The timer decrements a counter value
When the timer counter reaches "000016", it stops counting after reloading.
If a trigger occurs while counting, content of the reload register is reloaded into the
count register and counting resumes.
Divide Ratio
1/n n : setting value of the TAi register (i=0 to 4) 000016 to FFFF16,
but the timer counter does not run if n=000016
Counter Start Condition
The TAiS bit in the TABSR register is set to "1" (starts counting) and following triggers
occur:
• External trigger input is provided
• Timer counter overflows or underflows
• The TAiOS bit in the ONSF register is set to "1" (timer started)
Counter Stop Condition
• After the timer counter has reached "000016" and is reloaded
• When the TAiS bit is set to "0" (stops counting)
Interrupt Request Generation Timing The timer counter reaches "000016"
TAiIN Pin Function
Programmable I/O port or trigger input
TAiOUT Pin Function
Programmable I/O port or pulse output
Read from Timer
The value in the TAi register is indeterminate when read
Write to Timer
• When the timer counter stops, the value written to the TAi register is also written to
both reload register and counter
• While counting, the value written to the TAi register is written to the reload register
(It is transferred to the counter at the next reload timing)
NOTE:
1. The CNT3 to CNT0 bits in the TCSPR register select no division (n=0) or divide-by-2n (n=1 to 15).
Rev. 1.00 Nov. 01, 2005 Page 142 of 330
REJ09B0271-0100