Epson Stylus Photo Service Manual page 24

Chapter 1 Product Description
Following lists "Notes" when using Parallel Interface.
Note1) " 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.
Note2) Conditions for Interface are based on TTL level. Rise and fall time should be within 0.2 s.
Note3) Refer to the figure 1-9 for transmission timing of each signals.
Note4) Do not perform data transmission ignoring /ACK or BUSY signal. (Perform the data transmission
after confirming that /ACK and BUSY signals are Low.)
Note5) 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.
[Data Transmission Timing for Forward Channel]
Table 1-12. Maximum and Minimum Timing for Data Transmission
Parameter
tsetup
tready
tt-out*
tnbusy
* Rise and fall time of every output signals.
** Rise and fall time of every input signals.
Typical time of tack is shown below.
1-16
Figure 1-9. Parallel Interface Timing Chart (Forward Channel)
Minimum
thold
tstb
tbusy
tt-in**
treply
tack
tnext
Table 1-13. Typical Time of Tack
Parallel I/F mode
High speed
Normal speed
Maximum
500ns
500ns
500ns
0
---
---
---
0
500ns
0
0
Typical time of tack
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---
---
---
500ns
120ns
200ns
---
10us
---
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1us
3us
Rev.A