GM82C803CN Datasheet, PDF (23/84 Pages) List of Unclassifed Manufacturers – 2.88 MB FDC/ Dual UARTs with FIFO/PIO(EPP/ ECP)/ IDE Interface/ S-IR/ PnP

Table 4-4. ECP Register Definitions
Register
data
ecpAfifo
dsr
dcr
cFIFO
ecpDfifo
tFIFO
cnfgA
cnfgB
ecr
Address
Base addr + 000h
Base addr + 000h
Base addr + 001h
Base addr + 002h
Base addr + 400h
Base addr + 400h
Base addr + 400h
Base addr + 400h
Base addr + 401h
Base addr + 402h
GM82C803CN
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
R/W
R/W
Mode
000-001
011
ALL
ALL
010
011
110
111
111
ALL
Index
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
data (0x000 Modes 000,001 : Parallel Port Data Register)
This is the standard parallel port data register. Writing to this register in mode 000 shall drive data to the parallel
port data lines. In all other modes the drivers may be tri-stated by setting the direction bit in the dcr. Read to this
register return the value on the data lines.
ecpAFifo (0x000 Modes 011 : ECP FIFO - Address/ RLE)
A data byte written to these address is placed in the FIFO and tagged as a ECP Address / RLE. The gardware at the
ECP port will transmit this byte to the peripheral automatically. The operation of this register is only defined for
the forward direction (direction is 0).
Table. ECP Address FIFO
<7>
W
1:
0:
<6:0>
W
Indicates data Type
Bit <6:0> are a ECP Address
Bit field <6:0> is a run length, indicating how many times the next data byte
is to appear (0 = 1 time, 1 = 2 times, 2 = 3 times, etc.).
Address or RLE field described above.
dsr (0x001 : Device Status Register)
This read-only register reflects the inputs on the parallel port interface.
Table. Device Status Register
<7>
R
<6>
R
<5>
R
<4>
R
<3>
R
<2:0>
R
Busy
Ack
Error
Select
Fault
reserved
inverted version of parallel port Busy signal.
version of parallel port Ack signal.
version of parallel port Error signal.
version of parallel port Select signal.
version of parallel port Fault signal.
returns undefined when read.