Reverse data transfer phase: In nibble mode, setting this signal 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 data.

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 1284active (nSelectln) is set low, the IEEE 1284 idle phase is aborted and the interface returns to compatibility mode.

ECP mode: Used for reverse direction flow control. Also 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 deemed 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 1284 active is high.

nFault/nDataAvail/nPeriphRequest

Compatibility mode: Low signal indicates that an error occurred.

A-10Technical Specifications