W83977F Datasheet, PDF (96/181 Pages) Winbond – PLUG & PLAY 1.0A COMPLIANT

W83977F/ W83977AF
5.3 Extended Capabilities Parallel (ECP) Port
PRELIMINARY
This port is software and hardware compatible with existing parallel ports, so it may be used as a
standard printer mode if ECP is not required. It provides an automatic high burst-bandwidth channel
that supports DMA for ECP in both the forward (host to peripheral) and reverse (peripheral to host)
directions.
Small FIFOs are used in both forward and reverse directions to improve the maximum bandwidth
requirement. The size of the FIFO is 16 bytes. The ECP port supports an automatic handshake for
the standard parallel port to improve compatibility mode transfer speed.
The ECP port supports run-length-encoded (RLE) decompression (required) in hardware.
Compression is accomplished by counting identical bytes and transmitting an RLE byte that indicates
how many times the next byte is to be repeated. Hardware support for compression is optional.
For more information about the ECP Protocol, refer to the Extended Capabilities Port Protocol and
ISA Interface Standard.
5.3.1 ECP Register and Mode Definitions
NAME
ADDRESS
I/O
data
Base+000h
R/W
ecpAFifo
Base+000h
R/W
dsr
Base+001h
R
dcr
Base+002h
R/W
cFifo
Base+400h
R/W
ecpDFifo
Base+400h
R/W
tFifo
Base+400h
R/W
cnfgA
Base+400h
R
cnfgB
Base+401h
R/W
ecr
Base+402h
R/W
ECP MODES
000-001
011
All
All
010
011
110
111
111
All
FUNCTION
Data Register
ECP FIFO (Address)
Status Register
Control Register
Parallel Port Data FIFO
ECP FIFO (DATA)
Test FIFO
Configuration Register A
Configuration Register B
Extended Control Register
Note: The base addresses are specified by CR23, which are determined by configuration register or hardware setting.
MODE
000
001
010
011
100
101
110
111
DESCRIPTION
SPP mode
PS/2 Parallel Port mode
Parallel Port Data FIFO mode
ECP Parallel Port mode
EPP mode (If this option is enabled in the CR9 and CR0 to select ECP/EPP mode)
Reserved
Test mode
Configuration mode
Note: The mode selection bits are bit 7-5 of the Extended Control Register.
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Publication Release Date: January 1997
Revision 0.50