GMS84512 Datasheet, PDF (65/123 Pages) Hynix Semiconductor – 8-BIT SINGLE CHIP MICROCOMPUTER

GMS 84512 / 84524
3.7.2 Interrupt Interval Measurement Method
The following is a interrupt interval measurement method.
¨ç Select interrupt input port to be used by writing data to FUNC(00CA_H)
¨è To measure interrupt interval, select the edge of interrupt input signal by writing data to
IEDS( 00CB_H )
¨é Control to write data to IDCR (Interrupt interval measurement control register) .
When IDST(bit0 fo IDCR) is "1", counter is operating. If IDCK (bit1 of IDCR) selecting
measurement clock is "0", PS9(64§Á) is selected, otherwise PS8(32§Á) is selected.
If ISEL(bit of IDCR) selecting external interrupt input is "0", INT1 is selected, otherwise INT2
is selected.
¨ê If using edge of interrupt input signal is to be input automatically the value of counter is stored
to IDR(00EDH), after 1 machine cycle, counter is to be clear and go on count-up.
So, interrupt interval is measured continuously.
INTERRUPT INTERVAL DETERMINATION CONTROL REGISTER
IDCR
<00EC_H>
¦¡
¦¡
¦¡
¦¡
¦¡
R/W R/W R/W
7
6
5
4
3
2
1
0
¦¡
¦¡
¦¡
¦¡
¦¡ ISEL IDCK IDST
Initial Value(at RESET)
[ ---- -000 ]
No use
External INT. input selection
0 : INT1
1 : INT2
COUNTER Start/Stop Control
0 : Count Stop
1 : After Counter Clear Start Count-Up
Interval Measurement Clock Selection
0 : 64§Á
1 : 32§Á
Rising Edge
INT Input Signal
33H
8-bit Counter
After 1 Machine 1FH
Cycle
00_H
IDR
Start
Clear
?
Clear
1F_H
FIG 3.7.3 The example of Interrupt Interval Measurement
Clear
33_H
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