W83L517D_05 Datasheet, PDF (102/133 Pages) Winbond – LPC I/O for Notebook

W83L517D/W83L517D-F
9.3.12 ECP Pin Descriptions
NAME
nStrobe (HostClk)
PD<7:0>
nAck (PeriphClk)
TYPE
O
I/O
I
DESCRIPTION
The nStrobe registers data or address into the slave on the
asserting edge during write operations. This signal handshakes
with Busy.
These signals contains address or data or RLE data.
This signal indicates valid data driven by the peripheral when
asserted. This signal handshakes with nAutoFd in reverse.
Busy (PeriphAck)
PError (nAckReverse)
Select (Xflag)
This signal deasserts to indicate that the peripheral can accept
data. It indicates whether the data lines contain ECP command
I 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.
This signal is used to acknowledge a change in the direction of
the transfer (asserted = forward). The peripheral drives this
I signal low to acknowledge nReverseRequest. The host relies
upon nAckReverse to determine when it is permitted to drive
the data bus.
I Indicates printer on line.
nAutoFd (HostAck)
Requests a byte of data from the peripheral when it is asserted.
This signal indicates whether the data lines contain ECP
O 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.
Generates an error interrupt when it is asserted. This signal is
nFault (nPeriphRequest)
I
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.
This signal sets the transfer direction (asserted = reverse,
nInit (nReverseRequest) O deasserted = forward). This pin is driven low to place the
channel in the reverse direction.
nSelectIn (ECPMode)
O This signal is always deasserted in ECP mode.
9.3.13 ECP Operation
The host must negotiate on the parallel port to determine if the peripheral supports the ECP protocol
before ECP operation. After negotiation, it is necessary to initialize some of the port bits. The
following are required:
(a) Set direction = 0, enabling the drivers.
(b) Set strobe = 0, causing the nStrobe signal to default to the deasserted state.
(c) Set autoFd = 0, causing the nAutoFd signal to default to the deasserted state.
(d) Set mode = 011 (ECP Mode)
ECP address/RLE bytes or data bytes may be sent automatically by writing the ecpAFifo or ecpDFifo,
respectively.
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