UPD75238GJ NEC [NEC], UPD75238GJ Datasheet - Page 68

• Manufacturer Part Number: UPD75238GJ
• Description: 4 BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC [NEC]

68
(4) Time setting in the timer/event counter
[Timer set time] (period) is [value of the modulo register + 1] divided by [count pulse frequency] selected
by the timer mode register.
T(sec) =
T(sec) : Timer set time (seconds)
f
n
Once the timer is set, the interrupt request signal (IRQT0) is generated at set time intervals. Table 4-3
indicates the resolution and maximum set time (set when FFH is set in the modulo register) of the timer/
event counter for each count pulse signal.
CP
(Hz) : Count pulse frequency (Hz)
: Value in the modulo register (n = 0)
(n + 1)
f
CP
(When f
(When f
TM06
TM06
= (n + 1) • (resolution)
1
1
1
1
1
1
1
1
Mode register
Mode register
TM05
TM05
X
X
0
0
1
1
0
0
1
1
Table 4-3 Resolution and Maximum Set Time
= 6.0 MHz)
= 4.19 MHz)
TM04
TM04
0
1
0
1
0
1
0
1
Resolution
Resolution
42.7 s
10.7 s
2.67 s
61.1 s
15.3 s
3.81 s
171 s
244 s
Timer channel 0
Timer channel 0
Maximum set time
Maximum set time
43.7 ms
10.9 ms
2.73 ms
62.5 ms
15.6 ms
3.91 ms
683 s
977 s
PD75238