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CHAPTER 9 8-BIT TIMER/EVENT COUNTERS 2, 3 TM2, TM3
9.3 8-Bit Timer/Event Counters 2 and 3 Control Registers
The following two types of registers are used to control timers 2 and 3.
• Timer clock select register n (TCLn)
• 8-bit timer mode control register n (TMCn)
n = 2, 3
(1) Timer clock select register n (TCLn: n = 2, 3)
This register sets count clocks of timers 2 and 3.
TCLn is set with an 8-bit memory manipulation instruction.
RESET input sets to 00H.
Figure 9-3. Timer Clock Select Register 2 (TCL2) Format
Address: FF74H
After Reset: 00H
Symbol
7
TCL2
0
TCL22
0
0
0
0
1
1
1
1
Cautions 1. When rewriting TCL2 to other data, stop the timer operation beforehand.
2. Set bits 3 to 7 to 0.
Remarks
1. f
: Main system clock oscillation frequency
X
2. Figures in parentheses apply to operation with f
122
R/W
6
5
4
0
0
0
TCL21
TCL20
0
0
TIO2 Falling edge
0
1
TIO2 Rising edge
3
1
0
f
/2
X
5
1
1
f
/2
X
7
0
0
f
/2
X
8
0
1
f
/2
X
9
1
0
f
/2
X
11
1
1
f
/2
X
3
2
0
TCL22
Count Clock Selection
(1.04 MHz)
(261 kHz)
(65.4 kHz)
(32.7 kHz)
(16.3 kHz)
(4.09 kHz)
= 8.38 MHz
X
1
0
TCL21
TCL20
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