Operation Panel - Oki ML490 Maintenance Manual

2.1.7 Operation Panel

The clock synchronization OPCLK of LSI is used to input the switch data and output the LED
data through the operation panel control IC.
LSI
OPTD
OPCK
NPA2
OPRD
A 2-byte (15 bits + 1 even parity bit) command (OPTXD) is transmitted to the Operation panel
contol IC in synchronization with the OPCLK signal. The Operation panel control IC decodes
this command and when it is found to be legal, returns a 2-byte command response back to
the LSI which includes data on Switch information, LED status, receive command ACK/NAK and
1 odd parity bit.
Any transmission errors found cause the command to be reissued after the transmission of the
OPCLR-N signal.
42114101 Rev.1
Operation panel control IC
OPTXD
48
OPCLK
Command
47
and Data
OPCLR-N
latch
45
OPRXD
46
LED driver
+5V
Switch
controller
25 /