Epson 440 Manuale Utente
Chapter 1 Product Description
Rev. A
1-19
[Signal level: TTL compatible (IEEE-1284 level 1 device)]
Parameter
Minimum
Maximum
Condition
VOH*
---
5.5V
VOL*
-0.5V
---
IOH*
---
0.32mA
VOH = 2.4V
IOL*
---
12mA
VOL = 0.4V
CO
---
50pF
VIH
---
2.0V
VIL
0.8V
---
IIH
---
0.32mA
VIH = 2.0V
IIL
---
12mA
VIL = 0.8V
CI
---
50pF
Note)
*:
A low logic level on the Logic H signal is 2.0V or less when the printer is
powered off and this signal is equal or exceeding 3.0V when the printer is
powered on. The receiver shall provide an impedance equivalent to
7.5K ohm to ground.
powered off and this signal is equal or exceeding 3.0V when the printer is
powered on. The receiver shall provide an impedance equivalent to
7.5K ohm to ground.
[Data Transmission Timing for Reverse Channel]
The figure below shows timing chart of Parallel Interface Reverse channel.
1.3.2.1 Prevention Hosts from Data Transfer time-out
Generally, hosts abandon data transfer to peripherals when a peripheral is in the busy state for dozens of
seconds continuously. To prevent hosts this kind of time-out, the printer receives data very slowly,
several bytes per minute, even if the printer is in busy state. This showdown is started when the rest of
the input buffer becomes several hundreds of bytes. Finally, the printer is in the busy state continuously
when the input buffer is full.
seconds continuously. To prevent hosts this kind of time-out, the printer receives data very slowly,
several bytes per minute, even if the printer is in busy state. This showdown is started when the rest of
the input buffer becomes several hundreds of bytes. Finally, the printer is in the busy state continuously
when the input buffer is full.
Table 1-16. Signal Level
Virtual Busy Status
Virtual Busy Status
Figure 1-10. Parallel Interface Timing Chart(Reverse Channel)