Service manual

EPSON Stylus PHOTO 870/1270 Revision B
PRODUCT DESCRIPTIONS Interface 24
1.3.2 Parallel Interface (Reserve Channel)
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Transmission mode: IEEE-1284 nibble mode
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Adaptable connector See forward channel.
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Synchronization: Refer to the IEEE-1284 specification.
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Handshaking: Refer to the IEEE-1284 specification.
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Data trans. timing: Refer to the IEEE-1284 specification.
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Signal level: IEEE-1284 level 1 device (See forward
channel.)
NOTE: In/Out refers to the direction of signal flow from the printer’s point of view.
Table 1-14. Connector Pin Assignment and Signals
Pin No. Signal Name
Return
GND Pin
In/Out Functional Description
1 HostClk 19 In Host clock signal.
2-9 DATA0-7 20-27 In
The DATA0 through DATA7 signals represent data bits 0 to 7,
respectively. Each signal is at high level when data is logical 1
and low level when data is logical 0. These signals are used to
transfer the 1284 extensibility request values to the printer.
10 PtrClk 28 Out Printer clock signal.
11
PtrBusy / DataBit-
3,7
29 Out
Printer busy signal and reverse channel transfer data bit 3 or
7.
12
AckDataReq /
DataBit-2,6
28 Out
Acknowledge data request signal and reverse channel
transfer data bit 2 or 6.
13 Xflag / DataBit-1,5 28 Out X-flag signal and reverse channel transfer data bit 1 or 5.
14 HostBusy 30 In Host busy signal.
31 -INIT 30 In Not used.
32
-DataAvail /
DataBit-0,4
29 Out
Data available signal and reverse channel transfer data bit 0
or 4.
36 1284-Active 30 In 1284 active signal.
18 Logic-H - Out Pulled up to +5V via 3.9K ohm resistor.
35 +5V - Out Pulled up to +5V via 3.3K ohm resistor.
17 Chassis GND - - Chassis GND
16,33, 19-30 GND - - Signal GND
15,34 NC - - Not connected