Ieee-1284 Parallel I/F (Reverse Channel) - Epson STYLUS COLOR 480 Service Manual

EPSON Stylus COLOR 480

1.3.2 IEEE-1284 Parallel I/F (Reverse Channel)

Reverse channel is used to transfer the information data from the printer side to the PC
side.
Table 1-7. Parallel I/F Specification (R-Channel)
Item
Transmission mode IEEE-1284 nibble mode
Synchronization Comply with the IEEE-1284 specification
Handshaking Comply with the IEEE-1284 specification
Logic Level TTL level (IEEE-1284-Level 1 device)
Data trans. timing Comply with the IEEE-1284 specification
Extensibility request data The printer responds affirmatively when the extensibility request
values are 00H or 04H;
00H: Request Nibble Mode Reverse Channel Transfer.
04H: Request Device ID;
Return Data Using Nibble Mode Reverse Channel Transfer
o
Device ID
The printer sends following device ID string when it is requested.
[00H] [5AH]
MFG: EPSON;
CMD: ESCPL2, BDC, D4;(*1)
MDL: Stylus[SP]COLOR[SP]480;
CLS: PRINTER;
DES: EPSON[SP]Stylus[SP]COLOR[SP]480;
(*1): When the D4 mode (IEEE1284.4) is OFF, printer reply as follows.
CMD: ESCPL2,BDC
NOTE: [00H] denotes a hexadecimal value of zero.
MDL value depends on the EEPROM setting. Refer to Appendix.
Product Description
Specification
Interface Specification
The connector pin assignment is described in the table below. For these signals
described in the table, use the twist pair wire and connect the return side to the signal
GND.
Table 1-8. Connector Pin Assignment and Signals (F-Channel)
Return
Pin No. Signal Name
GND Pin
1 19 HostClk
2-9 20-27 Data1-8
10 28 PtrClk
PtrBusy/
11 29
DataBit-3,7
AckDataReq/
12 28
DataBit-2,6
Xflag/DataBit-
13 28
1,5
14 30 HostBusy
31 30 -INIT
-DataAvail/
32 29
DataBit-0,4
18 - Logic H
35 - +5V
17 - Chassis
16, 33
- GND
19-30
15, 34 - NC
36 30 1284-Active
Revision B
From Function Description
PC Host clock signal.
The DATA 1 through DATA8 signals
PC
represent data bits 1-8 respectively.
Printer Printer clock signal.
Printer busy signal and reverse channel
Printer
transfer data bit 3 or 7.
Acknowledge data request signal and
Printer
reverse channel transfer data bit 2 or 6.
X-flag signal and reverse channel
Printer
transfer data bit 1 or 5.
PC Host busy signal.
PC Not used.
Data available signal and reverse channel
Printer
transfer data bit 0 or 4.
Printer Pulled up to +5V via 3.9K ohm resistor.
Printer Pulled up to +5V via 3.3 K ohm resistor.
- Printer chassis GND.
- Signal GND
- Not used.
PC 1284 active signal.
22