FDC37B78X SMSC Corporation, FDC37B78X Datasheet - Page 97

• Manufacturer Part Number: FDC37B78X
• Description: Enhanced Super I/O Controller with ACPI Support/ Real Time Clock and Consumer IR
• Manufacturer: SMSC Corporation

The bit map of the Extended Parallel Port registers is:
Note 1: These registers are available in all modes.
Note 2: All FIFOs use one common 16 byte FIFO.
Note 3: The ECP Parallel Port Config Reg B reflects the IRQ and DRQ selected by the Configuration
ISA IMPLEMENTATION STANDARD
This specification describes the standard ISA
interface to the Extended Capabilities Port
(ECP). All ISA devices supporting ECP must
meet the requirements contained in this section
or the port will not be supported by Microsoft.
For a description of the ECP Protocol, please
refer to the IEEE 1284 Extended Capabilities
Port Protocol and ISA Interface Standard, Rev.
1.14, July 14, 1993. This document is available
from Microsoft.
Description
The port is software and hardware compatible
with existing parallel ports so that it may be
used as a standard LPT port if ECP is not
required. The port is designed to be simple and
requires a small number of gates to implement.
It does not do any "protocol" negotiation, rather
data
ecpAFifo
dsr
dcr
cFifo
ecpDFifo
tFifo
cnfgA
cnfgB
ecr
Registers.
Addr/RLE
compress
nBusy
PD7
D7
0
0
intrValue
MODE
nAck
PD6
D6
0
0
Direction
PError
PD5
D5
0
Parallel Port IRQ
Parallel Port Data FIFO
nErrIntrEn
ackIntEn
ECP Data FIFO
Select
PD4
Test FIFO
D4
1
97
Address or RLE field
it provides an automatic high burst-bandwidth
channel that supports DMA for ECP in both the
forward and reverse directions.
Small FIFOs are employed in both forward and
reverse directions to smooth data flow and
improve the maximum bandwidth requirement.
The size of the FIFO is 16 bytes deep. The port
supports an automatic handshake for the
standard parallel port to improve compatibility
mode transfer speed.
The port also 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
intercepts the RLE byte and repeats the
following byte the specified number of times.
Hardware support for compression is optional.
SelectIn
dmaEn
nFault
PD3
D3
be
0
repeated.
serviceIntr
PD2
nInit
D2
0
0
Parallel Port DMA
Decompression
autofd
PD1
full
D1
0
0
strobe
empty
PD0
D0
0
0
Note
simply
2
1
1
2
2
2