HD404639R Datasheet, PDF (65/135 Pages) Renesas Technology Corp – 4-Bit Single-Chip Microcomputer

Toggle output waveform (timers B, C, and D)
Free-running timer
HD404639R Series
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 52 and 59)
N: The value of the timer write register
Figure 43 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 as shown in figure 44.
It is reset to $0 by MCU reset.
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