CHAPTER 6 PERIPHERAL HARDWARE FUNCTION
139
User’s Manual U10676EJ3V0UM
[Timer set time] (cycle) is calculated by dividing [contents of modulo re 1] by [count pulse (CP)
frequency] selected by the mode register.
T (sec) =
= (n+1) (resolution)
where,
T (sec): Timer set time (seconds)
f
CP
(Hz): CP frequency (Hz)
n:
Contents of modulo register (n
≠
0)
Once the timer has been set, interrupt request flag IRQTn is set at the set time interval of the timer.
Table 6-7 shows the resolution of each count pulse of the timer counter and the longest set time (time when FFH
is set to the modulo register).
Table 6-7. Resolution and Longest Set Time (8-Bit Timer Counter Mode) (1/3)
(TM10 = 0, TM11 = 0, TM20 = 0, TM21 = 0)
(a)
µ
PD754244: at 6.0 MHz
8-bit timer counter (channel 0)
Mode Register
8-bit Timer Counter (Channel 0)
TM06
TM05
TM04
Resolution
Longest set time
1
0
0
171
µ
s
43.7 ms
1
0
1
42.7
µ
s
10.9 ms
1
1
0
10.7
µ
s
2.73 ms
1
1
1
2.67
µ
s
683
µ
s
8-bit timer counter (channel 1)
Mode Register
8-bit Timer Counter (Channel 1)
TM16
TM15
TM14
Resolution
Longest set time
0
1
1
5.33
µ
s
1.37 ms
1
0
0
683
µ
s
175 ms
1
0
1
171
µ
s
43.7 ms
1
1
0
42.7
µ
s
10.9 ms
1
1
1
10.7
µ
s
2.73 ms
n +1
f
CP
.