Printronix S828 Programmer's Manual page 368

Programmer Manual
PrtClk (nAck)
Compatibility Mode:
Negotiation Phase:
Reverse Data Transfer Used in both Nibble and Byte Modes to qualify data being sent to the host.
Phase:
PrtBusy (Busy)
Compatibility Mode:
Negotiation Phase:
Reverse Data Transfer Nibble Mode: Data bits 3 then 7, then forward channel busy status
Phase:
Reverse Idle phase: Forward channel busy status.
AckDataReq (PError)
Compatibility Mode:
Negotiation Phase:
Reverse Data Transfer Nibble Mode: Data bits then 6.
Phase:
Reverse Idle phase:
Xflag (Select)
Compatibility Mode:
Negotiation Phase:
Reverse Data Transfer Nibble Mode: Data bits 1 then 5.
Phase:
Reverse Idle phase:
Xflag (Select)
Compatibility Mode:
Negotiation Phase:
Xflag (Select)
Reverse Data Transfer Nibble Mode: Set low to indicate that host can receive printer-to-host data then set
Phase:
Reverse Idle phase:
Peripheral Logic High (+ 5V)
Set high to indicate that all other signals sourced by the printer are in valid state. Set low to indicate the
printer is off.
Appendix B‐ Interfaces
Pulsed low by the printer to acknowledge the transfer of a data from the host.
Set low to acknowledge 1284 support, then set high to indicate that the Xflag
(Select) and data available flags may be read.
Driven high to indicate that the printer is not ready to receive data.
Reflects the present state of the printer's forward channel.
Byte Mode: Forward channel busy status.
Driven high to indicate that the printer has encountered an error in the paper path.
The printer shall set nFault low whenever it sets PError high.
Set high to indicate 1284 support, then follows nDataAvail (nFault).
Byte Mode: same as nDataAvail (nFault)
Set high until host requests data transfer, then follows nDataAvail (nFault).
Set high to indicate that the printer in on-line.
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.
Byte Mode: Same as negotiation phase.
Same as negotiation phase.
Set low by host to put the printer into auto-line feed mode.
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.
high to acknowledge receipts of that nibble.
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.
Set high in response to PtrClk (nAck) low pulse to re-enter reverse data transfer
phase.
Is set high with 1284 Active (nSelectIn) being set low, the 1284 idle phase is being
aborted and the interface returns to Compatibility Mode.
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260071‐001A