5-7 OPE PBA
OPE PBA serves as the Machine-User interface.
The OPE operates on a time-sharing basis. As shown below, OPE keys and LED control are divided into
key scanning, LED displaytime and display time. On each 2ms interrupt rising edge, OPE line turns off
after 125µsec initial delay, and after 1 CPUCLK cycle, LEDCTL-LOW makes LED turn off. During the next
128 CPUCLK cycles, OPE KEY STROBE is maintained and during the next 1 CPUCLK KEY, INPUT is
scanned and stored in KEY buffer.
After key scanning, through the OPO0-3 port the upper and lower nibble data are transferred to the LCD
module as LCDCTL goes high.
After key displaying DATA on LCD, LED lamps turn on with LEDCTL-ON.
OPO0-4 : Used as key board strobe or LCD, LED driver
OPO5-7 : Used as key board strobe.
OPI0-3 : Key scanning ports from key matrix.
7
0
1
2
3
4
5
6
7
0
LED0
LED0
LED0 LED0
LED0
LED0 LED0
LED0 LED0
LED0
LED1
LED1
LED1 LED1
LED1
LED1 LED1
LED1 LED1
LED1
LED2
LED2
LED2 LED2
LED2
LED2 LED2
LED2 LED2
LED2
LED7
LED7
LED7 LED7
LED7
LED7 LED7
LED7 LED7
LED7
C2MS
125
µ
sec
LEDCTL
LEDCTL
LED
OFF
LED
ON
LCDCS
LCDCS
LCD HI
LCD H
LCD LO
LCD L
KB STROBE
[X] = Time Interval of TSTCLK's
IRQ2MS
IRQ2MS
OPO0
OPO1
OPO2
OPI0
OPI1
OPI2
OPI7
OPI[3:0]
OPO7
(7)
(7)
(128)
(12)
(16)
(1)
(1)
(3)
(1)
(7)
(1)
LED0
LED1
LED2
LED7
LCD DB0H LCD DB0L
LCD DB1L
LCD DB2L
LCD DB1H
LCD DB2H
5-10
SF150T