HD404629R Datasheet, PDF (72/157 Pages) Renesas Technology Corp – AS Microcomputer Incorporating a DTMF Generator Circuit

HD404629R Series
Registers for Timer C Operation: By using the following registers, timer C operation modes are selected
and the timer C count is read and written.
 Timer mode register C1 (TMC1: $00D)
 Timer mode register C2 (TMC2: $014)
 Timer write register C (TWCL: $00E, TWCU: $00F)
 Timer read register C (TRCL: $00E, TRCU: $00F)
• Timer mode register C1 (TMC1: $00D): Four-bit write-only register that selects the free-running/reload
timer function, input clock source, and the prescaler division ratio as shown in
figure 55. It is reset to $0 by MCU reset.
Writing to this register is valid from the second instruction execution cycle after the execution of the
previous timer mode register C1 write instruction. Setting timer C’s initialization by writing to timer
write register C (TWCL: $00E, TWCU: $00F) must be done after a mode change becomes valid.
Timer mode register C1 (TMC1: $00D)
Bit
Initial value
Read/Write
Bit name
3
0
W
TMC13
2
0
W
TMC12
1
0
W
TMC11
0
0
W
TMC10
TMC13
0
1
Free-running/reload timer selection
Free-running timer
Reload timer
TMC12 TMC11 TMC10 Input clock period
0
0
0
2048t_cyc
1
1024t_cyc
1
0
512t_cyc
1
128t_cyc
1
0
0
32t_cyc
1
8t_cyc
1
0
4t_cyc
1
2t_cyc
Figure 55 Timer Mode Register C1 (TMC1)
• Timer mode register C2 (TMC2: $014): Three-bit read/write register that selects the timer C output
mode as shown in figure 56. It is reset to $0 by MCU reset.
• Timer write register C (TWCL: $00E, TWCU: $00F): Write-only register consisting of the lower digit
(TWCL) and the upper digit (TWCU). The operation of timer write register C is basically the same as
that of timer write register B (TWBL: $00A, TWBU: $00B).
• Timer read register C (TRCL: $00E, TRCU: $00F): Read-only register consisting of the lower digit
(TRCL) and the upper digit (TRCU) that holds the count of the timer C upper digit. The operation of
timer read register C is basically the same as that of timer read register B (TRBL: $00A, TRBU: $00B).
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