Interface Control; Parallel Interface Control - Oki PACEMARK 4410 Service Manual

2.1.4

Interface control

The PM4410 is provided with the centronics parallel interface and RS-232C serial interface as
standard features.Also, it can be connected to the optional Network I/F Card. The interface cable
can be connected simultaneously with these interfaces.
These interfaces can be switched with the menu switch on the operation panel, in addition, you can
designate auto-select for them. The MPU communicates with hosts through the NHDC according
to the selected interface mode. The selected interface is stored to the EEPROM and can maintain
even after powering the printer off.
2.1.5

Parallel Interface Control

The Parallel data input from the host to the NHDC LSI is latched to its internal register at the falling
or rising edge of the STROBE-N signal.
At the same time, the LSI sets the BUSY signal to the high level to inform the host that the data
is being processed, and outputs the INT-P signal to inform the MPU of data reception. The data
is read upon receiving the RD-N signal from the MPU.
When the data processing ends, the BUSY signal is set to off and the ACK-N signal in sent to
request the next data. When reception is impossible because the buffer is full, the BUSY signal is
sent to request stopping of data transmission.
Data
1 to 8
STROBE
BUSY
ACK
INT
MPU
A/D bus
INT-P
INT
or
500ns max.
2~8µs
Figure 2.8
NHDC LSI
BSYP
ACKN
PSBN
INT
or
Line
Parallel I/F
driver
receiver
BUSY
ACK-N
STB-N
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