HD404654 Datasheet, PDF (54/111 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404654 Series
Toggle output waveform (timers C, and D)
Free-running timer
256 clock cycles 256 clock cycles
Reload timer
(256 – N)
clock cycles
(256 – N)
clock cycles
PWM output waveform (timers C and D)
T × (N + 1)
TMC13 = 0
TMD13 = 0
TMC13 = 1
TMD13 = 1
T ^{T × 256}
T × (256 – N)
Notes: The waveform is always fixed low when N = $FF.
T: Input clock period to counter (figures 37 and 44)
N: The value of the timer write register
Figure 36 Timer Output Waveform
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 37.
It is reset to $0 by MCU reset.
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