CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
Preliminary User’s Manual U19014EJ1V0UD
123
(4) Prescaler mode register 00 (PRM00)
PRM00 is the register that sets the TM00 count clock and TI000 and TI010 pin input valid edges.
Rewriting PRM00 is prohibited during operation (when TMC003 and TMC002 = other than 00).
PRM00 can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation sets PRM00 to 00H.
Cautions 1. Do not apply the following setting when setting the PRM001 and PRM000 bits to 11 (to
specify the valid edge of the TI000 pin as a count clock).
•
Clear & start mode entered by the TI000 pin valid edge
•
Setting the TI000 pin as a capture trigger
2. If the operation of the 16-bit timer/event counter 00 is enabled when the TI000 or TI010 pin is
at high level and when the valid edge of the TI000 or TI010 pin is specified to be the rising
edge or both edges, the high level of the TI000 or TI010 pin is detected as a rising edge.
Note this when the TI000 or TI010 pin is pulled up. However, the rising edge is not detected
when the timer operation has been once stopped and then is enabled again.
3. The valid edge of TI010 and timer output (TO00) cannot be used for the P01 pin at the same
time. Select either of the functions.
Figure 6-9. Format of Prescaler Mode Register 00 (PRM00)
Address: FFBBH After reset: 00H R/W
Symbol
7 6 5 4 3 2 1 0
PRM00 ES101 ES100 ES001 ES000
0
0 PRM001
PRM000
ES101
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
ES001
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
Count clock selection
PRM001 PRM000
f
PRS
= 12 MHz
f
PRS
= 16 MHz
0 0
f
PRS
12 MHz
16 MHz
0 1
f
PRS
/2
2
3 MHz
4 MHz
1 0
Setting
prohibited
1 1
TI000
valid
edge
Note
Note
The external clock requires a pulse two cycles longer than internal clock (f
PRS
).
Remark
f
PRS
: Peripheral hardware clock frequency
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