Epson Stylus COLOR 440 Service Manual page 30

EPSON Stylus COLOR 440, 640, and 740
The following are general notes on the parallel interface:


The Return GND Pin column in Tables 1-10 and 1-12 indicates a
twisted pair return, and is used for all control signals except Logic-H,
+5 V, Chassis GND, and NC. The return side is connected to GND
(pins 16, 33, and 19 to 30) in the twisted pair return. Since these
cables are shielded, you can reduce electrostatic noise by
connecting them to Chassis GND in both the printer and computer.


Interface conditions are based on TTL logic levels. Rise and fall times
should be less than 0.2 µ s.


See Figure 1-9 for the transmission timing of each signal.


Be sure to perform data transmission only after confirming that the
ACKNLG and BUSY signals are LOW.


You can perform a print test without using external equipment. Set
the 8-bit data signals (pins 20 through 27) to the appropriate word
code and connect them to the ACKNLG and STROBE signals.
Data Byte Data n
Thold
/STROBE
Tsetup
Tstrb
BUSY
Tready Tbusy
/ACKNLG
Figure 1-9. Data Transmission Timing for the Forward Channel
Byte Data n+1
Tnext
Treply Tack Tnbusy
Table 1-13.
Maximum and Minimum Timing for Data Transmission
Parameter
tsetup
thold
tstb
tready
tbusy
tt-out*
tt-in**
treply
tack
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 in Table 1-14 below.
Table 1-14. Typical Tack Timing
Parallel Interface Mode
High speed
Normal speed
Chapter 1 Product Description
Minimum Maximum
500ns —
500ns —
500ns —
0 —
— 500ns
— 120ns
— 200ns
0 —
500ns 10us
0 —
0 —
Typical Tack Timing
µ
2 s (Stylus COLOR 440 and 640)
µ
1 s (Stylus COLOR 740)
µ
4 s (Stylus COLOR 440 and 640)
µ
3 s (Stylus COLOR740)
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