Panasonic F77G User Manual page 271

Table 7-3-2 shows the clock source that can be selected.
Table 7-3-2
Count Timing of Timer Operation (Timer 7)
The binary counter counts up with the selected clock source as the count clock.
The basic operation of the whole function of 16-bit timer is as follows ;
Count
clock
TM7EN
flag
Preset
register
Compare
register
Binary
counter
Interrupt
request flag
Figure 7-3-1
(A) When any data is written to the preset register as the TM7EN flag is stopped ("0"), the same
value is loaded at the writing cycle and the binary counter is cleared to x'0000'.
(B) If the TM7EN flag is "1", the binary counter starts counting. The counting is happened at the
falling edge of the count clock.
Clock Source at Timer Operation(Timer 7)
Clock source
fosc
fosc/2
fosc/4
fosc/16
fs
fs/2
fs/4
fs/16
Notes : as fosc = 20 MHz fx = 32.768 kHz fs
= fosc/2 = 10 MHz
N
(A)
(A)
0000 0001 0002
(A) (B)
Count Timing of Timer Operation (Timer 7)
1 count time
50 ns
100 ns
200 ns
800 ns
100 ns
200 ns
400 ns
1.6 s
M
(C)
N
(D)
N-1 N 0000 0001
Chapter 7 16-bit Timer
M
0002 0003
(E)
VII - 11
16-bit Timer Count