EPSON Stylus PHOTO 810/820/830

Revision B

1.3.3 USB Interface

† Standard

 

 

 

: Based on

 

 

 

 

 

 

 

 

“Universal Serial Bus Specifications Rev. 1.1”

 

 

 

 

 

 

 

 

“Universal Serial Bus Device Class Definition

 

 

 

 

 

 

 

 

for Printing Devices Version 1.1”

† Bit Rate

 

 

 

: 12Mbps (Full Speed Device)

† Data Encoding

 

 

: NRZI

† Adaptable Connector

 

 

: USB Series B

† Recommended Cable Length : 2 meters

 

 

 

Table 1-15. Connector pin assignment and signals

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pin No.

Signal name

 

I/O

 

 

 

 

 

 

 

 

Function description

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

VCC

-

 

 

 

 

Cable power. Max. power consumption is 2mA.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

-Data

Bi-D

 

 

Data

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

 

+Data

Bi-D

 

 

Data, pull up to +3.3V via 1.5K ohm resistor.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

 

Ground

-

 

 

 

 

Cable ground

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pin #2

 

 

 

 

 

 

Pin #1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pin #3

Pin #4

Figure 1-9. USB pin Assignment
1.3.4 Prevention Hosts of 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 of time-out, the printer receives data very slowly, several bytes per minute, even if the printer is in busy state. This slowdown is started when the remaining input buffer becomes several hundreds of bytes, and the printer is finally in the busy state continuously when the input buffer is full.

USB and IEEE1284.4 on the parallel interface do not require this function.

1.3.5 Interface Selection

The printer has two built-in interfaces : the USB and parallel interface. These interfaces are selected automatically.

†Automatic Selection

In this automatic interface selection mode, the printer is initialized to the idle state scanning which interface receives data when it is powered on. Then the interface which receives data first is selected. When the host stops data transfer and the printer is in the stand-by state for seconds, the printer is returned to the idle state. As long as the host sends data or the printer interface is in busy state, the selected interface is let as it is.

†Interface State and Interface Selection

When the parallel interface is not selected, the interface gets into the busy state. When the printer is initialized or returned to the idle state, the parallel interface gets into the ready state. Caution that the interrupt signal such as the -INIT signal on the parallel interface is not effective while that interface is not selected.

1.3.6 IEEE1284.4 Protocol

The packet protocol described by IEEE1284.4 standard allows a device to carry on multiple exchanges or conversations which contain data and/or control information with another device at the same time across a single point-to-point link. The protocol is not, however, a device control language. It provides basic transport-level flow control and multiplexing services. The multiplexed logical channels are independent of each other and blocking of one has no effect on the others. The protocol operates over IEEE1284.

†Automatic Selection

An initial state is compatible interface and starts IEEE1284.4 communication when magic strings (1284.4 synchronous commands) are received.

PRODUCT DESCRIPTION

INTERFACE

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