HD404618 Datasheet, PDF (50/91 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404618 Series
T× (TCR + 1)
TMC3 = 0
TMC3 = 1
T × 256
T
T× (256 – TCR)
T: Period of clock input to the counter (table 23)
TCR: Value of timer load register C (0–255)
Note: This waveform is always fixed low
when TCR = $FF.
Figure 29 Variable-Duty Pulse Output Waveform
Timer Mode Register B (TMB: $009): Four-bit write-only register that selects the auto-reload function,
the prescaler division ratio, and input clock source as shown in table 22. Timer mode register B is
initialized to $0 by MCU reset.
Writing to this register is valid from the second instruction execution cycle. Timer B initialization set by
writing to TMB must be done after a mode change becomes valid.
Table 22 Timer Mode Register B
TMB
Bit 3
0
1
Auto-Reload Function
Disabled
Enabled
TMB
Bit 2
0
0
0
0
1
1
1
1
Bit 1
0
0
1
1
0
0
1
1
Bit 0
0
1
0
1
0
1
0
1
Prescaler Division Ratio, Clock Input Source
÷ 2048
÷ 512
÷ 128
÷ 32
÷8
÷4
÷2
INT₁ (external event input)
48