Interface Control - OKIDATA Microline 395 Service Handbook

%2.1.04 Interface Control

2.1.04 Interface Control
The Microline 395 is capable of serial or parallel operation. The desired interface method is selected by
sliding the interface cover to expose the desired connector. When this is done, the interface select switch
is turned ON or OFF to inform the Interface Control LSI (Q12) of the selected interface.
Parallel Interface
When the interface select switch is turned OFF, the parallel interface is selected and the Interface Control
LSI is in the parallel mode.
The data from the interface is received through connector (CN-1) and the Interface LSI (Q12) latches this
data to the internal register in the LSI at the rising edge of the STB-N signal.
The BUSY signal is turned ON as the data is processed. When processing is completed, the BUSY signal
is turned OFF and an ACK signal is sent to the host to request more data.
The BUSY signal is also turned ON when the printer is not able to receive data (buffer is full, printer is
deselected or an error condition exists).
RS232-C Serial Interface
When the interface select switch is turned ON, the serial interface is selected and the Interface Control
LSI is in the serial mode.
Then the RS232-C interface signals (DSR, CTS, CD and RD) are converted to TTL levels by the line
receiver (Q4) and input to the Master MPU, Slave MPU and MMU. The Master MPU converts the serial
data to parallel data.
The interface signals (DTR, RTS, SSD and TD) output from the Master MPU and Interface LSI are
converted from TTL levels to RS232-C levels by the line driver (Q2) and sent to the serial interface
connector.
ML395 ( 96-02-03 )