m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 131

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

[Precautions for event counter mode]
Fig. 7.4.9 Reading timer Ai register
TIMER A
[Precautions for event counter mode]
7-28
1. While counting is in progress, by reading the timer Ai (i = 0 to 9) register, the counter value can be read
2. The TAi
(1) For countdown
out at any timing. However, if the timer Ai register is read at the reload timing shown in Figure 7.4.9,
the value “FFFF
the period from when a value is set into the timer Ai register with the counter stopped until the counter
starts counting, the set value is correctly read out.
selected for each timer.
Counter value
Read value
Switching between countup and countdown by TAi
Pulse output function
Two-phase pulse signal processing function (Timers A2 to A4, A7 to A9)
(Hex.)
(Hex.)
n : reload register’s contents
OUT
pin is used for all functions listed below. Accordingly, only one of these functions can be
16
2
2
” (at an underflow) or “0000
1
1
0
0
Reload
FFFF n – 1
n
7905 Group User’s Manual Rev.1.0
Time
n – 1
16
” (at the overflow) is read out. If reading is performed in
(2) For countup
Counter value
OUT
Read value
pin’s input signal
(Hex.)
(Hex.)
n : reload register’s contents
FFFD FFFE FFFF
FFFD FFFE FFFF 0000 n + 1
Reload
n
Time
n + 1