CHAPTER 7 TIMER/COUNTER FUNCTION
User’s Manual U13850EJ4V0UM
183
Cautions 1. Before setting TOCn, be sure to stop the timer operation.
2. LVSn and LVRn are 0 when read after data have been set to them.
3. OSPTn is 0 when read because it is automatically cleared after data has been set.
4. Do not set OSPTn (to 1) when other than one-shot pulse output.
(4) Prescaler mode registers 00, 01 (PRM00, PRM01)
PRM0n selects a count clock of the 16-bit timer (TM0) and the valid edge of TI0n input. PRM00 and PRM01 are
set by an 8-bit memory manipulation instruction.
RESET input clears PRM00 and PRM01 to 00H.
Figure 7-5. Prescaler Mode Register 00 (PRM00)
After reset: 00H R/W
Address: FFFFF206H
7
6
5
4
3
2
1
0
PRM00
ES011
ES010
ES001
ES000
0
0
PRM01
PRM00
ES011
ES010
Selects valid edge of TI01
0
0
Falling edge
0
1
Rising edge
1
0
Setting prohibited
1
1
Both rising and falling edges
ES001
ES000
Selects valid edge of TI00
0
0
Falling edge
0
1
Rising edge
1
0
Setting prohibited
1
1
Both rising and falling edges
Count clock selection
f
XX
PRM02
Note 1
PRM01
PRM00
Count clock
20 MHz
Note 3
12.58 MHz
0
0
0
f
XX
/2
100 ns
158 ns
0
0
1
f
XX
/16
800 ns
1.3
µ
s
0
1
0
INTWTNI
−
−
0
1
1
TI00 valid edge
Note 2
−
−
1
0
0
f
XX
/4
200 ns
318 ns
1
0
1
f
XX
/64
3.2
µ
s
5.1
µ
s
1
1
0
f
XX
/256
12.8
µ
s
20.3
µ
s
1
1
1
Setting prohibited
−
−
Notes 1.
Bit 0 of the PRM01 register
2.
The external clock requires a pulse longer than twice that of the internal clock (f
XX
/2).
3.
Only for the V850/SB1.
Содержание MPD703030A
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