Epson Stylus Color 640 Service Manual page 29

EPSON Stylus Color 440/640/740
The following are the points to note when using the parallel Interface.
NOTE 1:"Return GND pin" in the table means twist pair return and is
used for all control signals except for Logic H,+5V, Chassis,
GND and NC. In this twist pair return, returning side is
connected to GND (16,33, 19-30 pin) for twist pair return. Also,
these cables are shielded wires and it is effective to connect to
each chassis GND in the PC and printer for electrostatic noise.
NOTE 2:Conditions for Interface are based on TTL level. Rise and fall time
should be within 0.2 s.
NOTE 3:Refer to Figure 1-9 for transmission timing of each signals.
NOTE 4:Do not perform data transmission ignoring /ACK or BUSY
signal. (Perform the data transmission after confirming that /
ACK and BUSY signals are Low.)
NOTE 5:It is possible to perform the printing test including interface circuit
without using equipment from outside when 8-bit data signal
(20-27 pin) is set to appropriate word code and connect them
forcefully to /ACK and /STRB.
Chapter 1 Product Description
Byte Data n
Data
Thold
/STROBE
Tsetup
Tstrb
BUSY
Tready Tbusy
/ACKNLG
Treply
Figure 1-9. Data Transmission Timing for Forward Channel
Table 1-13.
Maximum and Minimum Timing for Data Transmission
Parameter Minimum
tsetup 500ns
thold 500ns
tstb 500ns
tready
tbusy
tt-out*
tt-in**
treply
tack 500ns
tnbusy
tnext
* Rise and fall time of every output signal.
** Rise and fall time of every input signal. Typical timing for the tack
parameter is shown below.
Revision A
Byte Data n+1
Tnext
Tack Tnbusy
Maximum
---
---
---
0 ---
--- 500ns
--- 120ns
--- 200ns
0 ---
10us
0 ---
0 ---
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