GMS84512 Datasheet, PDF (63/123 Pages) Hynix Semiconductor – 8-BIT SINGLE CHIP MICROCOMPUTER

GMS 84512 / 84524
3.7. Interrupt Interval Measurement Circuit
GMS84512/84524 is equipped with distinct edge of input signal for 2 channel external interrupt
(INT1, INT2) and interrupt interval measurement circuit of evaluating distinct edge interval.
Interrupt interval measurement circuit is equipped with interrupt input multiplexer, 8bit binary up-
counter measurement clock selection circuit, interrupt interval storage circuit and interrupt interval
measurement control register
3
7
IDCR
2
0
¡ª ¡ª ¡ª ¡ ª ¡ª ISEL IDCK IDST
Data BUS
PS8
32§Á
PS9
64§Á
1
MUX
0
IDST
ck _{8-bit Up-Counter}
Delay _Clear
8
Circuit
INT2
INT1
1
MUX
0
Interrupt Interval Data
Register
8
IDR
Data BUS
FIG. 3.7.1 Configruation of interrupt interval measurement circuit
3.7.1 Operation of Interrupt Interval Measurement Circuit
Interrupt interval measurement circuit stores the count value of 8-bit up counter to IDR(interrupt
interval data register) by selected edge of external interrupt input. And then it may clear 8-bit
up-counter, go on counting again. And the counter value of 8-bit up-counter is stored to IDR by
selected edge of second external interrupt input.
So, selected edge interval of external interrupt input is measured to PS8(32§Á) or PS9(64§Á).
Rising/Falling edge of interrupt input signal is selected by IEDS(External Interrupt Signal Edge
Selection)and width or period of input signal is measured by combination of selected edge.
External interrupt input signal is selected by FUNC(port function selection register)
Fig 3.7.2 and TABLE 3.7.1 show interrupt input signal edge selection and measurement interval.
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