Epson Stylus SCAN 2000 Service Manual page 19

EPSON Stylus Scan 2000
Table 1-4. Reverse channel pin assignments and signals (continued)
Return
Pin # Signal Name
GND pin
nReverseReque
31 30
st
nPeriphReques
32 29
t
36 1284-Active 30
18 Periph-Logic H -
35 +5V -
17 Chassis GND -
16, 33
GND -
19-30
15,34 NC -
3. Data trans. timing Refer to the IEEE-1284 specification and the following.
DATA data byte n
t
-STROBE
t
setup
BUSY
t
ready
-ACKNLG
Product Description
In/Out Description
This signal goes low to change to the
In
reverse channel.
Out This signal produces a host interrupt.
In 1284 active signal, High in ECP mode.
Always high. Pulled up to +5V via 3.9KΩ
Out
resistor
Always high. Pulled up to +5V via 1.0KΩ
Out
resistor
- Chassis GND
- Signal GND
- Not connected.
data byte n + 1
hold
t
next
t
stb
t
busy
t t
t
reply
ack nbusy
Table 1-5. Data transmission times
Parameter Minimum
tsetup 500 ns
thold 500 ns
tstb 500 ns
tready
tbusy
tt-out*
tt-in**
treply
tack 500 ns
tnbusy
tnext
* Rise and fall time of every output signal
** Rise and fall time of every input signal
Table 1-6. Typical tack time
Parallel I/F mode
High speed
Normal speed
* The Logic H signal goes low, 2.0 V or less, when the printer is turned off and goes high, 3.0
V or more, when the printer is turned on. The receiver shall provide an impedance equivalent
to 7.5 KΩ to ground.
4. Extensibility Request:
The printer responds affirmatively when the extensibility request values are 00H or
04H, which mean
n
00H Request nibble mode reverse channel transfer
Interfaces
Maximum
-
-
-
0 -
- 500 ns
- 120 ns
- 200 ns
0 -
10 us
0 -
0 -
Time required
1 us
3 us
Revision A
18