Epson Stylus COLOR 900 Service Manual page 26

EPSON Stylus COLOR 900/900N
Table 1-14 shows pin assignments for the reverse channel.
Pin No.
1 HostClk
2-9 Data0-7
10 PrtClk
11 PtrBusy, Data Bit-3,7
12 AckData Req, DataBit-2,6
13 Xflag, DataBit-1,5
14 HostBusy
31 /INIT
32 /DataAvail, DataBit-0,4
36 1284-Active
18 Logic-H
35 +5V
17 Chassis GND
16,33, 9-30 GND
15,34 NC
* In/Out refers to the direction of signal flow from the printer's point of view.
Table 1-14. Pin Assignment For Reverse Channel
Return GND
Signal Name
Pin
19
20-27
28
29
28
28
30
30
29
30
—
—
—
—
—
In/Out Functional Description
I Host clock signal.
The DATA0 through DATA7 signals represent data bits 0 to7,
respectively. Each signal is HIGH when data is logical 1 and LOW
I
when data is logical 0. These signals are used to transfer the 1284
extensibility request values to the printer.
O Printer clock signal.
O Printer busy signal and reverse channel transfer data bit 3 or 7.
Acknowledge data request signal and reverse channel transfer
O
data bit 2 or 6.
O X-flag signal and reverse channel transfer data bit 1 or 5.
I Host busy signal.
I Not used.
O Data available signal and reverse channel transfer data bit 0 or 4.
I 1284 Active signal
O Pulled up to +5 V via 3.9K ohm resister.
O Pulled up to +5 V via 3.3K ohm resister.
— Chassis GND.
— Signal GND.
— Not connected.
Chapter 1 Product Description
21