The Negotiation Phase; Signals - InfoPrint 6500-v05 User Manual

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.

The Negotiation Phase

The negotiation phase determines which operating mode will be used. At this time,
the host and the printer will sense what devices are attached, the supported signals
available, and which mode to use. The selected mode, in turn, defines the pins on
the 1284 connector.
There are 36 pins on the parallel interface. Each one sends a different signal. Pin 1,
for example, can send a Strobe signal or a HostC1k signal, depending on the mode
selected. See Table 9 for the different connector signals.

Signals

Table 9 lists each of the signals associated with the corresponding pins on the 1284
interface. Descriptions of the signals follow.
Table 9. 1284 Signals
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Source of Data Compatible
Host
Host/Printer Data 1 (LSB)
Host/Printer
Host/Printer
Host/Printer
Host/Printer
Host/Printer
Host/Printer
Host/Printer Data 8 (MSB)
Printer
Printer
Printer
Printer
Host nAutoFd
Not Defined
Logic Grid
Chassis Grid
Printer
Type of Mode
Nibble
nStrobe HostClk
Data 2
Data 3
Data 4
Data 5
Data 6
Data 7
nAck PtrClk
Busy PtrBusy
PError AckDataReq
Select Xflag
Host Busy
Peripheral Logic High
Signal Ground (nStrobe)
Signal Ground (Data 1)
Signal Ground (Data 2)
Signal Ground (Data 3)
Chapter 5. Printer Interfaces
Byte
Host/Clk
PtrClk
PtrBusy
AckDataReq
Xflag
HostAck
203