INTERFACE INFORMATION
Pin
No. Return
Pin No. Signal Name Direction Description
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).
User's Manual D-5