CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
Preliminary User’s Manual U16898EJ1V0UD
88
(4) Prescaler mode register 00 (PRM00)
This register is used to set the 16-bit timer counter 00 (TM00) count clock and the TI000, TI010 pin input valid
edges.
PRM00 is set by a 1-bit or 8-bit memory manipulation instruction.
Reset input sets the value of PRM00 to 00H.
Figure 6-8. Format of Prescaler Mode Register 00 (PRM00)
Address: FF61H After reset: 00H R/W
Symbol
7 6 5 4 3 2 1 0
PRM00 ES110 ES100 ES010 ES000
0
0 PRM001
PRM000
ES110
ES100
TI010 pin valid edge selection
0 0
Falling
edge
0 1
Rising
edge
1 0
Setting
prohibited
1
1
Both falling and rising edges
ES010
ES000
TI000 pin valid edge selection
0 0
Falling
edge
0 1
Rising
edge
1 0
Setting
prohibited
1
1
Both falling and rising edges
PRM001
PRM000
Count clock selection
0 0
f
XP
(10 MHz)
0 1
f
XP
/2
2
(2.5 MHz)
1 0
f
XP
/2
8
(39.06 kHz)
1
1
TI000 pin valid edge
Note
Note The external clock requires a pulse longer than two cycles of the internal count clock (f
XP
).
Cautions 1. Always set data to PRM00 after stopping the timer operation.
2. If the valid edge of the TI000 pin is to be set as the count clock, do not set the clear/start
mode and the capture trigger at the valid edge of the TI000 pin.
3. If the TI000 or TI010 pin is high level immediately after system reset, the rising edge is
immediately detected after the rising edge or both the rising and falling edges are set as
the valid edge(s) of the TI000 pin or TI010 pin to enable the operation of 16-bit timer
counter 00 (TM00). Be careful when pulling up the TI000 pin or the TI010 pin. However,
when re-enabling operation after the operation has been stopped once, the rising edge is
not detected.
4. When using P31 as the input pin of the TI010 pin valid edge, it cannot be used as a timer
output (TO00). When using P31 as the TO00 pin, it cannot be used as the input pin of the
TI010 pin valid edge.
Remarks 1. f
XP
: Oscillation frequency of clock supplied to peripheral hardware
2. ( ): f
XP
= 10 MHz
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