Epson Stylus Scan 2000, Service Manual

Page: 18 / 264

EPSON Stylus Scan 2000 Revision A
Product Description Interfaces 17
1.3 Interfaces
This section is divided into printer and scanner interface specifications. See the following
section for printer interface details or see “Scanner interfaces” on page 21 for scanner
interface details.
1.3.1 Printer interface
PARALLEL
BUSY signal is set high before setting either -ERROR low or PE high, and held high until
all these signals return to their inactive state.
BUSY signal is at high level in the following cases:
n
During data entry (see data transmission timing)
n
When input data buffer is full
n
During -INIT signal is at low level or during hardware initialization
n
During printer error (see -ERROR signal)
n
When the parallel interface is not selected
ERROR signal is at low level when the printer is in one of the following states:
n
Printer hardware error (fatal error)
n
Paper-out error
n
Paper-jam error
n
Ink-out error
PE signal is at high level during paper-out error.
1. Specifications
Transmission mode 8 bit parallel, IEEE-1284 ECP compatibility/nibble mode
Synchronization Refer to the IEEE-1284 specification
Handshaking Refer to the IEEE-1284 specification
Packet Refer to the IEEE-P1284.4 Standard for Data Delivery and
Logical Channels for IEEE Std. 1284 Interface (Draft D1.50)
Signal level TTL compatible level (IEEE-1284 Level 1 device)
Data trans. timing Refer to the IEEE-1284 specification
2. Connector pin assignment and signals
Table 1-4. Reverse channel pin assignments and signals
Pin # Signal Name
Return
GND pin
In/Out Description
1 HostClk 19 In
Data or address information transferred
from host to product.
2 DATA0 20 In
The DATA0 through DATA7 signals
represent data bits 0 to 7, respectively.
Each signal is high when data is logical 1
and low when data is logical 0.
These signals are used to transfer the 1284
extensibility request values to the printer.
3 DATA1 21 In
4 DATA2 22 In
5 DATA3 23 In
6 DATA4 24 In
7 DATA5 25 In
8 DATA6 26 In
9 DATA7 27 In
10 PeriphClk 28 Out Data transferred from product to host.
11 PeriphAck 29 Out
Printer busy signal and reverse channel
transfer data bit 3 or 7
12 nAckReverse 28 Out
Printer goes to Low and approves
nReverseRequest
13 Xflag 28 Out
X-flag signal and reverse channel transfer
data bit 1 or 5
14 HostAck 30 In
Host uses this signal for flow control in
reverse direction. Also this signal offers
the data bit 9 that is used to judge whether
the data or command will be sent on the
data signal in forward direction.