User's Manual

User's ManualD-6
INTERFACE INFORMATION
Pin Return Signal Direc- Description
No. Pin No. name tion
14 – Host Busy Input Reverse data transfer phase:
This signal is set low when the
host can receive data, and goes
high when the host has received
data. Following a reverse data
transfer, the interface enters the
reverse idle phase when the Host
Busy signal goes low and the
printer has no data.
Reverse idle phase:
This signal goes high when the
Printer Clock signal goes low so
that the interface re-enters the
reverse data transfer phase. If it
goes high with the 1284 Active
signal low, the 1284 idle phase is
aborted and the interface returns
to the compatibility mode.
32 –
Data Available Output Reverse data transfer phase:
This signal is set low when the
printer is ready to send data to
the host. During the data
transfer, it is used as data bit 0
(LSB), then data bit 4.
Reverse idle phase:
This signal is used to indicate
that data is available.
36 – 1284 Active Input This signal goes high to cause the
printer to enter the reverse data
transfer phase (nibble mode).