HD404356 Datasheet, PDF (56/100 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer

HD404358 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 C (TMC: $00D)
Port mode register A (PMRA: $004)
Timer write register C (TWCL: $00E, TWCU: $00F)
Timer read register C (TRCL: $00E, TRCU: $00F)
• Timer mode register C (TMC: $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 43. 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 C 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 C (TMC: $00D)
Bit
Initial value
Read/Write
Bit name
3
0
W
TMC3
2
0
W
TMC2
1
0
W
TMC1
0
0
W
TMC0
TMC3
0
1
Free-Running/Reload
Timer Selection
Free-running timer
Reload timer
TMC2
0
1
TMC1
0
1
0
1
TMC0
0
1
0
1
0
1
0
1
Input Clock Period
2048t_cyc
1024t_cyc
512t_cyc
128t_cyc
32t_cyc
8t_cyc
4t_cyc
2t_cyc
Figure 43 Timer Mode Register C (TMC)
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