TIMER A
[Precautions for event counter mode]
[Precautions for event counter mode]
1. Each of timers A3, A5 to A8 is not equipped with the event counter mode.
2. While counting is in progress, by reading the timer Aj (j = 0 to 2, 4, 9) register, the counter value can
be read out at any timing. However, if the timer Aj register is read at the reload timing shown in Figure
7.4.9, the value “FFFF16” (at an underflow) or “000016” (at the overflow) is read out. If reading is
performed in the period from when a value is set into the timer Aj register with the counter stopped until
the counter starts counting, the set value is correctly read out.
(1) For countdown
(2) For countup
Reload
Reload
Counter value
(Hex.)
Counter value
(Hex.)
n
2
2
1
1
0
0
n – 1
n
n + 1
FFFE FFFF
FFFD
Read value
(Hex.)
Read value
(Hex.)
n – 1
n + 1
FFFD FFFE FFFF
0000
FFFF
Time
Time
n : reload register’s contents
n : reload register’s contents
Fig. 7.4.9 Reading timer Aj register
3. The TAjOUT pin is used for all functions listed below. Accordingly, only one of these functions can be
selected for each timer.
ꢀ Switching between countup and countdown by TAjOUT pin’s input signal
ꢀ Pulse output function
ꢀ Two-phase pulse signal processing function (Timers A2, A4, A9)
7906 Group User’s Manual Rev.2.0
7-28
RENESAS [ RENESAS TECHNOLOGY CORP ]
