Compuprint 10200 Programmer Manual User Manual
Page 219
Interfaces
215
Xflag (Select)
Compatibility Mode:
Set high to indicate that the printer in on-line.
Negotiation Phase:
The Xflag refers to extendibility flag. Used by the printer to reply to the
requested extendibility byte sent by the host during the negotiation phase.
The signal level is low for Nibble Mode, high for Byte Mode.
Nibble Mode:
Data bits 1 then 5.
Reverse Data Transfer
Phase:
Byte Mode:
Same as negotiation phase.
Reverse Idle Phase:
Same as negotiation phase.
HostBusy (nAutofd)
Compatibility Mode:
Set low by host to put the printer into auto-line feed mode.
Negotiation Phase:
Set low in conjunction with 1284 Active (NSelectIn) being set high to request
a 1284 mode.
Then set high after printer sets PtrClk (nAck) low.
Nibble Mode:
Set low to indicate that host can receive printer-to-host data
then set high to acknowledge receipts of that nibble.
Reverse Data Transfer
Phase:
Byte Mode:
Same as Nibble Mode to request and acknowledge bytes.
Following a reverse channel transfer the interface transitions
to idle phase when HostBusy (nAutoFd) is set low and
printer‘s no data available.