PACSZ1284 Datasheet, PDF (5/7 Pages) California Micro Devices Corp – P/ACTIVE IEEE 1284 ECP/EPP TERMINATION NETWORK

PACSZ1284
Application Information
Termination Considerations
The IEEE 1284 specification requires both termination
and EMI filtering on a total of 17 signal lines. Control
and Status lines (8 in total) only require a pull-up resis-
tor and a filter capacitor. The Data lines and Strobe
also require a series termination resistor in addition to
the pull-up resistors and filter capacitors. See Table 1,
in conjunction with the schematic diagram on page 1.
Table 1: IEEE 1284 Termination Requirements
SIGNAL TERMINATION REQUIREMENTS
Signal Name
Data1 - Data8
Strobe
Init
AutoFeedXT
Selectin
ACK
Busy
Paper Empty
Select
Fault
Series Termination
Yes
Yes
Not Required
Not Required
Not Required
Not Required
Not Required
Not Required
Not Required
Not Required
Interfacing to IEEE 1284 Connectors
IEEE 1284 defines three interface connectors:
• 1284 A is a 25-pin DB series connector which is
the de facto PC standard for the host connection.
• 1284 B is a 36-pin, 0.085 inch centerline connector
used on the peripheral device.
• 1284 C is a new 36-pin, 0.050 inch centerline con-
nector which can be used for both host and periph-
eral.
Figure 3A shows a possible hook-up between the
1284-A connector on a PC motherboard and the
PACSZ1284, illustrating how the pin configuration of
the PACSZ1284 allows for easy interconnect between
the two. The dotted I/O signals of the PACSZ1284 will
typically be connected to a Super I/O chip on the
motherboard.
Figure 3B shows a possible hook-up between the
1284-B connector on a peripheral and the PACSZ1284.
Figure 3C shows a possible hook-up between the
1284-C connector and the PACSZ1284.
Figure 3A:
Figure 3B:
1284-A Connector
Host
14
25
1
13
1284-B Connector
Peripheral
19
1
PASCUPSEZR1122884
1
= FLOW
= ^TG^HRN^OUD^GH
=
V^SIGNALS
CC
PASUCPSEZR1122844
1
Figure 3C:
1284-C Connector
Host/Peripheral
36
20
19
2
18
1
36
18
= GND
= V_CC
PASUCPSEZR1122844
1
Figure 3. Example Connections of IEEE 1284 Connectors with PACSZ1284
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