Renesas M16C/60 Series Hardware Manual page 120

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M16C/6N5 Group
Table 1.13.3 Specifications in Event Counter Mode (when processing two-phase pulse signal with timers A2, A3 and A4)
Item
Count source
Count operation
Divide ratio
Count start condition
Count stop condition
Interrupt request generation timing
TAi pin function
IN
TAi pin function
OUT
Read from timer
Write to timer
Select function (Note)
i = 2 to 4
j = 2, 3
k = 3, 4
Note : 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.1.00 2003.05.30 page 106
• Two-phase pulse signals input to TAi
• Up-count 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.
1/ (FFFF - n + 1) for up-count
16
1/ (n + 1) for down-count
Set TAiS bit of TABSR register to "1" (start counting)
Set TAiS bit to "0" (stop counting)
Timer overflow or underflow
Two-phase pulse input
Two-phase pulse input
Count value can be read by reading timer A2, A3 or A4 register
• 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)
• Normal processing operation (timer A2 and timer A3)
The timer counts up rising edges or counts down falling edges on TAj
when input signals on TAj
TAj
OUT
TAj
IN
Up-
count
• Multiply-by-4 processing operation (timer A3 and timer A4)
If the phase relationship is such that TAk
nal on TAk pin is "H", the timer counts up rising and falling edges on
OUT
TAk and TAk pins. If the phase relationship is such that TAk
OUT IN
"L" when the input signal on TAk
and falling edges on TAk
TAk
OUT
Count up all edges
TAk
IN
• Counter initialization by Z-phase input (timer A3)
The timer count value is initialized to "0" by Z-phase input.
Specification
or TAi
IN OUT
n : set value of TAi register
pin is "H".
OUT
Up- Up- Down-
count count count
pin goes "H" when the input sig-
IN
pin is "H", the timer counts down rising
OUT
and TAk pins.
OUT IN
Count down all edges
Count up all edges Count down all edges
Timer A
pins
0000 to FFFF
16 16
pin
IN
Down- Down-
count count
pin goes
IN