Service manual

1.3.1.2 Reverse Channel
Transmission mode: 8-bit parallel, IEEE-1284 nibble mode.
Synchronization: Refer to the IEEE-1284 specification.
Handshaking: Refer to the IEEE-1284 specification.
Signal level: IEEE-1284 level 1 device (See the forward channel.)
Adaptable connector: The same as for the forward channel.
Data transmission timing: Refer to the IEEE-1284 specification.
Table 1-3 shows connector pin assignments and signal functions of the 8-bit parallel interface for reverse
channel.
Table 1-3. Signal and Connector Pin Assignments for the Parallel Interface
(Reverse Channel)
Pin No. Signal Name
Return
GND Pin
I/O* Description
1 Host Clk 19 I Host clock signal.
2 - 9 DATA 0 - 7 20 - 27 I
DATA 0-7 signals represent data bits 0 - 7,
respectively. Each signal is at a 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 Ptr Clk 28 O Printer clock signal.
11
Ptr Busy / Data
Bit 3, 7
29 O
Printer busy signal and reverse channel transfer data
bits 3, 7.
12
Ack Data Req /
Data Bit 2, 6
28 O
Acknowledge data request signal and reverse channel
transfer data bits 2, 6.
13
Xflag / Data Bit
1, 5
28 O
X-flag signal and reverse channel transfer data bits
1, 5.
14 Host Busy 30 I Host busy signal.
31
INIT 30 I Not used.
32
Data Avail / Data
Bit 0, 4
29 O
Data available signal and reverse channel transfer
data bits 0, 4.
36 1284-Active 30 I 1284 active signal.
18 Logic-H — O
A HIGH signal indicates that all other signals sourced
by the peripheral are in valid status.
35 +5V — O
Pulled up to +5 V via 3.3K Ω resistor.
17 Chassis GND — — Chassis GND.
16, 33,
19 - 30
GND — — Signal GND.
15, 34 NC — — Not connected.
* : The I/O column indicates the direction of the signal as viewed from the printer.
Product Description Stylus Pro XL+
1-6 Rev.A