Rev. 1.00
- 46 -
SRP-275II
3-5-2 IEEE1284 Parallel Interface
*Related model: IFG-P
Bi-directional parallel interface : In accordance with the IEEE 1284 Nibble / Byte mode
3-5-2(a) Forward Mode Specification (Compatibility mode)
Data transmission from host computer to printer : Centronics compatible
Item
Description
Remark
Data transmission
• 8 bit parallel
Synchronization
• External supplied nStrobe signals
Handshaking
• nACK and Busy signals
Signal level
• TTL compatible
Connector •
IEEE1284
TYPE-B
3-5-2(b) Reverse Mode Specification (Nibble / Byte mode)
Data transmission from the printer to the host computer. The STATUS data transmission from the printer to
the host computer is accomplished in the Nibble or Byte mode. This mode allows data transmission from the
asynchronous printer under the control of the host computer. Data transmission in the Nibble mode are made
via the existing control lines in units of bits(Nibble). In the Byte mode, data transmission are proceeded by
making the 8-bits data lines bidirectional. Neither mode can operate at the same time as the compatibility
mode, so switching is always required.
3-5-2(c) Signal Specification (Compatibility/Nibble/Byte mode)
Pin no.
Source
Compatibility mode
Nibble mode
Byte mode
1 Host
nStrobe
HostClk
HostClk
2
Host / Printer
Data 0 (LSB)
-
Data 0 (LSB)
3
Host / Printer
Data 1
-
Data 1
4
Host / Printer
Data 2
-
Data 2
5
Host / Printer
Data 3
-
Data 3
6
Host / Printer
Data 4
-
Data 4
7
Host / Printer
Data 5
-
Data 5
8
Host / Printer
Data 6
-
Data 6
9
Host / Printer
Data 7 (MSB)
-
Data 7 (MSB)
10 Printer
nAck
PtrClk
PtrClk
11
Printer
Busy
PtrBusy / Data3,7
PtrBusy
12
Printer
Perror
AckDataReq / Data2,6
AckDataReq
13
Printer
Select
Xflag / Data1,5
Xflag
14 Host
nAutoFd
HostBusy HostBusy
15 -
NC
ND
ND
16 -
GND
GND
GND
17 -
GND
FG
FG
18 Printer
Logic-H
Logic-H
Logic-H
19~30 -
GND
GND
GND
31 Host
nInit
nInit
nInit
32 Printer
nFault
nDataAbail
/
nDataAvail
33 -
NC
ND
ND
34 Printer
NC
ND
ND
35 Printer
NC
ND
ND
36 Host
nSelectln
1284-Active 1284-Active