Ieee1284 Parallel Interface - Samsung SRP-275 Service Manual

3-5-2 IEEE1284 Parallel Interface

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
Data transmission
Synchronization
Handshaking
Signal level
Connector
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
1 Host
2 Host / Printer
3 Host / Printer
4 Host / Printer
5 Host / Printer
6 Host / Printer
7 Host / Printer
8 Host / Printer
9 Host / Printer
10 Printer
11 Printer
12 Printer
13 Printer
14 Host
15 -
16 -
17 -
18 Printer
19~30 -
31 Host
32 Printer
33 -
34 Printer
35 Printer
36 Host
Rev. 2.00
Description
• 8 bit parallel
• External supplied nStrobe signals
• nACK and Busy signals
• TTL compatible
• IEEE1284 TYPE-B
Compatibility mode
nStrobe
Data 0 (LSB)
Data 1
Data 2
Data 3
Data 4
Data 5
Data 6
Data 7 (MSB)
nAck
Busy
Perror
Select
nAutoFd
NC
GND
GND
Logic-H
GND
nInit
nFault
NC
NC
NC
nSelectln
Nibble mode
HostClk
-
-
-
-
-
-
-
-
PtrClk
PtrBusy / Data3,7
AckDataReq / Data2,6
Xflag / Data1,5
HostBusy
ND
GND
FG
Logic-H
GND
nInit
nDataAbail /
ND
ND
ND
1284-Active
- 45 -
SRP-275
Remark
Byte mode
HostClk
Data 0 (LSB)
Data 1
Data 2
Data 3
Data 4
Data 5
Data 6
Data 7 (MSB)
PtrClk
PtrBusy
AckDataReq
Xflag
HostBusy
ND
GND
FG
Logic-H
GND
nInit
nDataAvail
ND
ND
ND
1284-Active