Tally T5023+ Programming Manual page 392

Description of the physical interface
XFlag/Select
Compatibility Mode:
ECP Mode:
HostAck/nAutoFd
Compatibility Mode:
ECP Mode:
Peripherial Logic High
nReverseRequest / nInit
Compatibility Mode:
ECP Mode:
382
(Printer driven)
Set 'high' to indicate that the printer is on-line.
Used by the printer to reply to the requested
extensibility byte sent by the host during the
negotiation phase.
(Host driven)
The interpretation of this signal varies from
printer to printer. Set 'low' by host to put some
printers into auto-line feed mode.
The host drives this signal for flow control in the
reverse direction. It is used in an interlocked
handshake with PeriphClk.
HostAck also provides a ninth data bit used to
determine whether command or data
information is present on the data signals in the
forward direction.
(Printer driven)
Set 'high' to indicate that all other signals
sourced by the printer are in a valid state.
Pulsed 'low' to reset the interface and force a
return to Compatibility Mode idle phase.
This signal is driven 'low' to place the channel in
the reverse direction.
T5023/5023+ - Programming Guide
Appendix