Application information ST1284
4/9 DocID6976 Rev 5
Figure 4. Functional diagram
2 Application information
The functional diagram here above presents a IEEE1284-A connector pinout and show how
to connect the ST1284 in order to correctly terminate and filter the 17 signal lines. The
IEEE1284-A connector is the PC standard for the host connection.
Control and status lines (from 10 to 17) only require a pull-up resistor (R
p
) and a filter
capacitor (C).
The data lines (from 2 to 9) and the strobe (pin 1) also require a termination series resistor
(R
s
) in addition to the pull-up resistor and a filter capacitor. The V
CC
is connected to pin 20
and the ground to pin 22.
The ST1284 can be used with all 3 types of connectors defined in the IEEE1284 standard:
• IEEE1284-A is a DB 25 connector which is the PC standard for the host connection.
• IEEE1284-B is a 36 pin, 0.085 inch center line connector used on the peripheral
device.
• IEEE1284-C is a new 36 pin, 0.050 inch center line connector which can be used for
both host and peripherals.
14 Autofeed
15 Error
16 Reset
17 Select in
1 Strobe
2 Bit 1
3 Bit 2
4 Bit 3
5 Bit 4
6 Bit 5
7 Bit 6
8 Bit 7
9 Bit 8
13 Select paper
14
1
13
25
1
28
2
27
20
26
25
24
23
21
19
18
17
16
3
4
5
6
7
9
11
13
14
8
10
12
15
22
10 Acknowledge
11 Busy
12 Paper Out
Vcc
Vcc
Vcc
Gnd
ST1284-xxA8
