To: 73544.665@compuserve.com From: Jaap van Ganswijk Subject: Re: National 87332 Cc: Bcc: X-Attachments: Hi Cliff, At 07:32 PM 9/19/95 -0400, you wrote: >Maybe I didn't look hard enough but I wasn't able >to find any info on the National 87332. >It's used to control the parallel port in my laptop >which I'm trying to build an interface for. It's quite difficult to get data on these kinds of chips: They are not in the normal data books and selector guides, since they are only used by very specialized users. These chips are also constantly changing, since they have a very short life cycle. The basic I/O-hardware hasn't changed much since the first PC-AT, so you can probably look at the schematics of any pc-board with a printer interface on it. The programming interface is for example described in: - The programmers PC Sourcebook - Thom Hogan - Microsoft press - Penguin books - ISBN 1-55615-118-7 But you can probably also find this info on the net in files like: inter34.zip, interrup.zip, ibmref34.zip and dosref34.zip. Here is the centronics parallel connector description from the book: 9.32. CENTRONICS PARALLEL CONNECTOR Pin # Definition Direction 1 -Strobe In 2 Data l In 3 Data 2 In 4 Data 3 In 5 Data 4 In 6 Data 5 In 7 Data 6 In 8 Data 7 In 9 Data 8 In 10 -Acknowledge (Active Low) Out 11 Busy Out 12 Paper End Out 13 Select Out 14 -AutoFeed (Active Low) In 15 NOT USED 16 Logical ground 17 Chassis ground 18 INOT USED 19 Ground return for -Strobe 20 Ground return for Data 1 21 Ground return for Data 2 22 Ground return for Data 3 23 Ground return for Data 4 24 Ground return for Data 5 25 Ground return for Data 6 26 Ground return for Data 7 27 Ground return for Data 8 28 Ground return for -Acknowledge 29 Ground return for busy 30 Ground 31 -Printer Init (Active Low) in 32 -Fault (Active Low) Out 33 Ground 34 NOT USED 35 Pulled to +5V through 4.7K ohm resistor 36 -Select In (Active Low) In Notes: Connector is an Amphenol 57-30360 or equivalent (Centronics parallel) Source: IBM Technical Reference Options and Adapters Volume 1, pages Graphics Printer 29 to 31 See Also: 9.04. RS-232C Serial Port Connector (DTE Device) 9.31. PS/2 Parallel Port Connector 9.34. Parallel Printer Connector Here is the connector on the PC-side: 9.34. PARALLEL PRINTER CONNECTOR Pin# irection Name Active Function I Out Strobe Low Indicates valid data available 2 Out Data bit 0 High Least significant bit of data byte 3 Out Data bit 1 High 4 Out Data bit 2 High 5 Out Data bit 3 High 6 Out Data bit 4 High 7 Out Data bit 5 High 8 Out Data bit 6 High 9 Out Data bit 7 High Most significant bit of data 10 In Acknowledge Low Indicates data received and device is ready for more 11 In Busy High Device cannot receive data 12 In P.End High Device is "out of paper" 13 In Select High Device is in "selected state" 14 Out Auto Feed Low Device to perform line feed after each line sent 15 In Error Low Device unable to perform 16 Out Initialize printer Low Reset device to initial state 17 In Select input Low Device can accept input 18 NA Ground NA 14 NA Ground NA 20 NA Ground NA 21 NA Ground NA 22 NA Ground NA 23 NA Ground NA 24 NA Ground NA 25 NA Ground NA Notes: ·Connector used is a female DB-25 ·The original printer adapter and monochrome display adapter parallel ports are output-only; no provision for parallel input was made until introduction of the PS/2 Source: IBM Technical Reference Options and Adapters Volume 2, page Printer Adapter 7 See Also: 9.31. PS/2 Parallel Port Connector 9.32. Centronics Parallel Connector Hope this helps, Jaap