Epson TM-U950P - B/W Dot-matrix Printer Specification page 158

Termination refers to the processing to return to the Compatibility Mode from either Nibble or
Byte Mode.
To terminate either the Nibble or Byte Mode, the host must take the following actions.
• To set 1284-Active(nSelectIn) low.
• To set HostBusy(nAutoFd) high (event 22).
Termination is available in two types.
À
Handshake between the host and the printer
Á
Immediate termination
À
In the case of , on the condition that, in the process of transition from Reverse Mode to
Compatibility Mode, the event 22 has been completed while the interface is active (with 1284-
Active set high);
1) The printer responds to the 1284-Active by setting PtrBusy(Busy) and nDataAvail(nFault) high
(event 23).
2) The printer will then reverse Xflag(Select) and set PtrClk(nAck) low (event 24).
3) The host then sets HostBusy(nAutoFd) low (event 25).
4) The printer then sets nDataAvail(nFault), Xflag(Select) and AckDataReq(PError) back to the
status in the Compatibility Mode (event 26) and sets PtrClk(nAck) high (event 27).
5) The host completes the termination handshake by setting HostBusy(nAutoFd) high, returning
the interface to the Compatibility Mode Idle phase (event 28).
6) The printer then changes PtrBusy(Busy) to be ready to accept data from the host.
Á