HD404459 Datasheet, PDF (64/122 Pages) Renesas Technology Corp – 4-bit HMCS400-series microcomputers

HD404459 Series
Toggle output waveform (timers B, C, and D)
Free-running timer
256 clock cycles
Reload timer
256 clock cycles
(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 × 256
T
T × (256 – N)
Note: The waveform is always fixed low when N = $FF.
T: Input clock period to counter (figures 45, 53, and 60)
N: The value of the timer write register (figures 55, 56, 62, and 63)
Figure 44 Timer Output Waveform
Registers for Timer B Operation: By using the following registers, timer B operation modes are selected
and the timer B count is read and written.
 Timer mode register B1 (TMB1: $009)
 Timer mode register B2 (TMB2: $013)
 Timer write register B (TWBL: $00A, TWBU: $00B)
 Timer read register B (TRBL: $00A, TRBU: $00B)
 Port mode register C (PMRC: $025)
• Timer mode register B1 (TMB1: $009): Four-bit write-only register that selects the free-running/reload
timer function, input clock source, and the prescaler division ratio (figure 45). It is reset to $0 by MCU
reset.
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