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ECP Parallel (technical)
This file is designed to give a basic overview of the port found in most newer PC computers
called ECP Parallel port.
This file is not intended to be a thorough coverage of the standard. It is for informational
purposes only, and is intended to give designers and hobbyists sufficient information to design
their own ECP compatible devices.
Signal Descriptions:
nStrobe
This signal is registers data or address into the slave on the assering edge
during .
data 0-7
Contains address, data or RLE data. Can be used in both directions.
nAck
Valid data driven by the peripheral when asserted. This signal handshakes
with nAutoFd in reverse.
Busy
This signal deasserts to indicate that the peripheral can accept data. In
forward direction this handshakes with nStrobe. In the reverse direction
this signal indicates that the data is RLE compressed by being low.
PError
Used to acknowledge a change in the direction of transfer. High=Forward.
Select
Printer is online.
nAutoFd
Requests a byte of data from the peripheral when asserted, handshaking
with nAck in the reverse direction. In the forward direction this signal
indicates whether the data lines contain ECP address or data.
nFault
Generates an error interrupt when asserted.
nInit
Sets the transfer direction. High=Reverse, Low=Forward.
nSelectIn
Low in ECP mode.
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