Oki Microline 3320 - Preparing the Loading Tray

2 – 15
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 LSI (IC1: BU5148S).
LSI
OPTXD
OPCLK
OPCLR-N
OPRXD
77
78
80
OPTD
OPCK
NPA2
OPRD
Command
and Data 
latch
LED driver
Switch
controller
+5V
79
A 2-byte (15 bits + 1 even parity bit) command (OPTXD) is transmitted to the LSI (BU5148S)
in synchronization with the OPCLK signal. The LSI 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.