SATO GL4XXE Manual de Serviço descarregar pdf (Página 22)

Unit 3: Interface Specifications

GL4xxe Service Manual

3-5

IEEE1284 PARALLEL INTERFACE

The parallel interface is a standard connection in the GL4xxe series printers. It conforms to IEEE1284

specifications. It supports three operating modes, which are determined by negotiation between the printer and the

host.

Compatibility Mode: This mode provides compatibility with Centronics-like host I/O. Data is transferred from the

host to the printer in 8-bit bytes over the data lines. Compatibility Mode can be combined with Nibble and Byte

Modes to provide bidirectional communication.

Nibble Mode: Eight bits equals one byte. When a byte of data is sent to the printer, the eight bits are sent over

eight data lines. Some devices cannot send data over their eight data lines. To bypass this, the IEEE 1284 permits

data to be sent as half a byte over four status lines. (Half a byte equals one nibble.) Two sequential four-bit nibbles

are sent over the lines. Data is transferred from printer to host in four-bit nibbles over the status lines, and the host

controls the transmission.

Byte Mode: The printer and host send data to each other along eight data lines (one bit per line). If bidirectional

communication is supported by the printer and the host, the host will take control of the data transfer.

Table of IEEE1284 signals

PIN SOURCE

OF DATA

Type of Mode

Compatible Nibble Byte

1 Host nStrobe HostClk Host/Clk

2 Host/Printer Data 1 (LSB)

3 Host/Printer Data 2

4 Host/Printer Data 3

5 Host/Printer Data 4

6 Host/Printer Data 5

7 Host/Printer Data 6

8 Host/Printer Data 7

9 Host/Printer Data 8 (MSB)

10 Printer nAck PtrClk PtrClk

11 Printer Busy PtrBusy PtrBusy

12 Printer PError AckDattaReq AckDattaReq

13 Printer Select Xflag Xflag

14 Host nAutoFd Host Busy HostAck

15 Not defined

16 Logic Grid

18 Printer Peripheral Logic High

19 Signal Ground (nStrobe)

1 2 ... 17 18 19 20 21 22 23 24 25 26 27 ... 203 204

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