GMS87C4060 Datasheet, PDF (53/102 Pages) Hynix Semiconductor – 8-BIT SINGLE-CHIP MICROCONTROLLERS

PRELIMINARY
GMS81C4040/87C4060
15. Interrupt interval measurement circuit
The Interrupt interval measurement circuit is shown in Fig-
ure 15-1 .
The Interrupt interval measurement circuit consists of the
input multiplexer, sampling clock multiplexer, Edge detec-
tor, 8bit counter, measured result storing register, FIFO
(9bit, 6level) interrupt, Control register, etc.
The more details about registers are shown Figure 15-2 .
IDCR [F9_H] ^{FCLR IMS I34H I34L}
ISEL IDCK IDST
IDFS [FA_H] ^DPOL
FOE FFUL FEMP
PS8
PS9
INT3
INT4
1
MUX
0
1
MUX
0
Edge detector
8bit counter
Clear
Overflow
84
INTV
0
MUX
1
FCLR
FIFO
(9bit, 6level)
IDR [FB_H] ^{D7 D6 D5 D4 D3 D2 D1 D0}
Figure 15-1 Block Diagram of Interrupt interval measurement circuit
Control
The GMS81C4040/GMS87C4060 contains a Interrupt in-
terval measurement module.
1. Select interrupt input pin what you want to measure by
set the FUNC1 [00CE_H].
2. Set IDCR [00F9_H] : FIFO clear, interrupt mode, inter-
rupt edge select, external interrupt select between INT3
and INT4, sampling clock select.
3. Set IDCR [00F9_H] : set IDST to start measuring.
4. Counter value is stored to IDR [00FB_H] when selected
edge is detected. After data was written, timer is cleard au-
tomatically and it counts continue.
5. You can select interrupt occuring point by set Interrupt
Mode Select bit (IMS), every edge what you selected or
FIFO 4 level is filled.
6. If input signal’s interval is larger than maximum counter
value (0FF_H), counter occurring an interrupt and count
again from 00_H.
7. See Figure 15-4 FIFO operating mechanism.
Nov. 1999 Ver 1.0
PRELIMINARY
49