W83697HF/F
6.3.12 ECP Pin Descriptions
NAME
TYPE DESCRIPTION
nStrobe (HostClk)
O
The nStrobe registers data or address into the slave on the
asserting edge during write operations. This signal handshakes
with Busy.
PD<7:0>
I/O
I
These signals contains address or data or RLE data.
nAck (PeriphClk)
This signal indicates valid data driven by the peripheral when
asserted. This signal handshakes with nAutoFd in reverse.
Busy (PeriphAck)
I
This signal deasserts to indicate that the peripheral can accept
data. It indicates whether the data lines contain ECP command
information or data in the reverse direction. When in reverse
direction, normal data are transferred when Busy (PeriphAck) is
high and an 8-bit command is transferred when it is low.
PError (nAckReverse)
I
This signal is used to acknowledge a change in the direction of
the transfer (asserted = forward). The peripheral drives this signal
low to acknowledge nReverseRequest. The host relies upon
nAckReverse to determine when it is permitted to drive the data
bus.
Select (Xflag)
I
Indicates printer on line.
nAutoFd (HostAck)
O
Requests a byte of data from the peripheral when it is asserted.
This signal indicates whether the data lines contain ECP address
or data in the forward direction. When in forward direction, normal
data are transferred when nAutoFd (HostAck) is high and an 8-bit
command is transferred when it is low.
nFault (nPeriphRequest)
I
Generates an error interrupt when it is asserted. This signal is
valid only in the forward direction. The peripheral is permitted (but
not required) to drive this pin low to request a reverse transfer
during ECP Mode.
nInit (nReverseRequest)
nSelectIn (ECPMode)
O
O
This signal sets the transfer direction (asserted = reverse,
deasserted = forward). This pin is driven low to place the channel
in the reverse direction.
This signal is always deasserted in ECP mode.
Publication Release Date: Feb. 2002
- 76 -
Revision 0.70
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