HD404339 Datasheet, PDF (41/80 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer with large-capacity memory

Timer mode register A (TMA: $008)
Bit
Initial value
Read/Write
Bit name
3
0
W
TMA3
2
0
W
TMA2
1
0
W
TMA1
0
0
W
TMA0
HD404339 Series
Source Input Clock
TMA3 TMA2 TMA1 TMA0 Prescaler Frequency Operating Mode
0
0
0
0 PSS
2048 t_cyc Timer A mode
1 PSS
1024 t_cyc
1
0 PSS
512 t_cyc
1 PSS
128 t_cyc
1
0
0 PSS
32 t_cyc
1 PSS
8 t_cyc
1
0 PSS
4 t_cyc
1 PSS
2 t_cyc
1
0
0
0 PSW
32t_Wcyc Time-base
mode
1 PSW
16t _Wcyc
1
0 PSW
8t _Wcyc
1 PSW
2t _Wcyc
1
0
0 PSW
1/2t _Wcyc
1 Not used
1 X PSW and TCA reset
X = Don’t care.
Notes: 1. t _Wcyc = 244.14 µs (when a 32.768-kHz crystal oscillator is used)
2. Timer counter overflow output period (seconds) = input clock period (seconds) × 256.
3. The division ratio must not be modified during time-base mode operation,
otherwise an overflow cycle error will occur.
Figure 28 Timer Mode Register A (TMA)
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