Epson Stylus Color, Service Manual

Page: 24 / 151

Chapter 1 Product Description
Rev.A
1-16
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
µ
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]
Parameter Minimum Maximum
tsetup 500ns ---
thold 500ns ---
tstb 500ns ---
tready 0 ---
tbusy --- 500ns
tt-out* --- 120ns
tt-in** --- 200ns
treply 0 ---
tack 500ns 10us
tnbusy 0 ---
tnext 0 ---
* Rise and fall time of every output signals.
** Rise and fall time of every input signals.
Typical time of tack is shown below.
Parallel I/F mode Typical time of tack
High speed 1us
Normal speed 3us
DATA
/STRB
BUSY
/ACK
data byte n data byte n+1
t
hold
t
setup
t
stb
t
next
t
ready
t
busy
t
reply
t
ack
t
nbusy
Min. 500 ns
Min. 500 ns
Min. 500 ns
Min. 500 ns
Max. 500 ns Min. 0
Min. 0 Min. 0
Min. 0
Max. 10 us
tt-out Max. 120 ns : Rise and fall time of every output signals
tt-in Max. 200 ns : Rise and fall time of everu input signals
Typical value of tack takes followig values according to Parallel I/F speed(by the settin of
EEPROM 24H).
High speed (default) 1 us.
Ordinary 3us
Figure 1-9. Parallel Interface Timing Chart (Forward Channel)
Table 1-12. Maximum and Minimum Timing for Data Transmission
Table 1-13. Typical Time of Tack