Epson Stylus Color 200 User Manual page 111

Data transmission
timing:
Extensibility request:
Reverse channel pin assignments
Pin
no. Signal name
1 HostClk
2 DATA0
3 DATA1
4 DATA2
5 DATA3
6 DATA4
7 DATA5
8 DATA6
9 DATA7
10 PtrClk
11 PtrBusy/
DataBit-3,7
12 ACkDataReq/
DataBit-2,6
13 Xflag/
DataBit-1,5
A-12
Technical Specifications
Refer to the IEEE-1284 specification
The printer responds to the extensibility
request in the affirmative when the
request is 00H or 04H, which means:
00H: Request nibble mode of reverse
channel transfer
04H: Request device ID in nibble mode of
reverse channel transfer
GND In/Out*
19 In
20 In
21 In
22 In
23 In
24 In
25 In
26 In
27 In
28 Out
29 Out
28 Out
28 Out
Description
Strobe pulse. Input data is
latched at falling edge of
the signal.
These signals represent
information in bits 0 to 7 of
parallel data respectively.
Each signal is at HIGH level
when data is logical 1 and
LOW when it is logical 0.
These signals are used to
transfer the 1284 extensibility
request values to the printer.
Used to qualify data being
sent to the host. Set LOW
then HIGH to cause an
interrupt indicating to host
that data is available.
Data bits 3 then 7 indicate
forward channel busy status.
Data bits 2 then 6. Set HIGH
until host requests data
transfer, then follows
n Data Avail ( n Fault).
X flag signal and reverse
channel transfer data bits 1
then 5.