105
CHAPTER 7 16-BIT TIMER 0 TM0
(3) Prescaler mode register (PRM0)
This register is used to set 16-bit timer (TM0) count clock and valid edge of TI0n (n = 0 to 2) input.
PRM0 is set with an 8-bit memory manipulation instruction.
RESET input sets PRM0 value to 00H.
Figure 7-4. Prescaler Mode Register (PRM0) Format
Address: FF70H After Reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
PRM0
ES21
ES20
ES11
ES10
ES01
ES00
PRM01
PRM00
ES21
ES20
TI02 Valid Edge Selection
0
0
Falling edge
0
1
Rising edge
1
0
Setting prohibited
1
1
Both falling and rising edges
ES11
ES10
TI01 Valid Edge Selection
0
0
Falling edge
0
1
Rising edge
1
0
Setting prohibited
1
1
Both falling and rising edges
ES01
ES00
TI00 Valid Edge Selection
0
0
Falling edge
0
1
Rising edge
1
0
Setting prohibited
1
1
Both falling and rising edges
PRM01
PRM00
Count Clock Selection
0
0
f
X
/2
3
0
1
f
X
/2
4
1
0
f
X
/2
5
1
1
f
X
/2
6
Caution
Timer operation must be stopped before setting PRM0.
Summary of Contents for mPD780973 Series
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