nAutoFd/HostBusy/H ostAck
Compatibility mode: Not used.
negotiation phase: In order to request 1284 mode, this signal is set lo w an d
IEEE 1284 Active (nSelectln) is set high. Afterwards, this signal is set high
when PtrClk (nAck ) is set low.
reverse data transfer phase: In nibble mode, setting this si gnal low
indicates to the printer that the host is ready to receive data. When this
signal is subsequently set high, it indicates that the host received the da ta .
reverse idle phase: This signal is set high in response to a PtrClk (nAck)
low pulse in order to return to the reverse data phase. If this signal is set
high at the same time that IEEE 1284 Active (nSelec tl n) is set low the IEEE
1284 idle phase is aborted and the interface returns to compat ibility mode.
ECP mode: Used for reverse direction flow control. A lso used for
handshaking via PeriphClk (nAck).
NC
Not used.
PeripheralLogicHigh
Parallel B: NC.
Parallel C: Pull up to +5V with 3.9 KΩ.
nlnit/nReverseRequest
Compatibility mode: When a low signal is detected, the printer is de em ed
to be BUSY until the low signal is released.
negotiation phase: Always high.
reverse data transfer phase: Always high.
ECP mode: Low when switching to reverse direction. The peripheral
device has permission to drive the data signals only when this signal is
low and IEEE 1284 Active is high.
LAlbatross Rev.c
A5 size Appendix A
96/08/23 pass 0
A-10 Technical Specifications