M16C28 Datasheet, PDF (126/423 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/28 Group (M16C/28, M16C/28B)
12. Timer
Table 12.3 Specifications in Event Counter Mode
(when processing two-phase pulse signal with timers A2, A3 and A4)
Item
Specification
Count source
• Two-phase pulse signals input to TAiIN or TAiOUT pins (i = 2 to 4)
Count operation
• Increment or down-count can be selected by two-phase pulse signal
• When the timer overflows or underflows, it reloads the reload register con-
tents and continues counting. When operating in free-running mode, the
timer continues counting without reloading.
Divide ratio
1/ (FFFF16 - n + 1) for increment
1/ (n + 1) for down-count n : set value of TAi register 000016 to FFFF16
Count start condition
Set TAiS bit in the TABSR register to “1” (start counting)
Count stop condition
Set TAiS bit to “0” (stop counting)
Interrupt request generation timing Timer overflow or underflow
TAiIN pin function
Two-phase pulse input
TAiOUT pin function
Two-phase pulse input
Read from timer
Count value can be read by reading timer A2, A3 or A4 register
Write to timer
• When not counting and until the 1st count source is input after counting start
Value written to TAi register is written to both reload register and counter
• When counting (after 1st count source input)
Value written to TAi register is written to reload register
(Transferred to counter when reloaded next)
Select function (Note) • Normal processing operation (timer A2 and timer A3)
The timer counts up rising edges or counts down falling edges on TAjIN pin
when input signals on TAjOUT pin is “H”.
TAjOUT
TAjIN
(j=2,3)
Increment Increment
Increment Decrement Decrement Decrement
• Multiply-by-4 processing operation (timer A3 and timer A4)
If the phase relationship is such that TAkIN(k=3, 4) pin goes “H” when the
input signal on TAkOUT pin is “H”, the timer counts up rising and falling
edges on TAkOUT and TAkIN pins. If the phase relationship is such that
TAkIN pin goes “L” when the input signal on TAkOUT pin is “H”, the timer
counts down rising and falling edges on TAkOUT and TAkIN pins.
TAkOUT
Increment all edges
TAkIN
(k=3,4)
Decrement all edges
Increment all edges
Decrement all edges
• Counter initialization by Z-phase input (timer A3)
The timer count value is initialized to 0 by Z-phase input.
Notes:
1. Only timer A3 is selectable. Timer A2 is fixed to normal processing operation, and timer A4 is fixed to
multiply-by-4 processing operation.
Rev. 2.00 Jan. 31, 2007 ^{page 106} of 385
REJ09B0047-0200