Prime 3B (Mark II) based MultiIO card details


Following the appearance of my deductions regarding the jumper settings for a Prime3B-based card, I was contacted by Andrew Su regarding a card he had based on the Prime3B mark II chip. More specifically, his card contained chips with the following LGS part numbers: I'm not sure which of these was the Prime3B Mark II chip.

Specifications and jumper use on the Prime3B Mark II MultiIO card

Andrew has scanned in the documentation for his card, which is available for download here. Although not mentioned, the jumper block's pin 1 is located closest to the top of the card when it is placed component side up with the ISA connector at the bottom. For those without the resources to view such a large JPEG, the contents are summarised below.

Card features

Connector description

Port addresses

Jumper settings

JP5 and JP6 select the printer port mode: J13 and J14 select the IRQs for UART1 and UART2 respectively. These jumper blocks have 10 sets of pins numbered from 1 to 10, going from left to right. These correspond to IRQs 15, 14, 13, 12, 11, 10, 3, 4, 5 and 7 respectively.

Possible problems and inconsistancies

According to Andrew, the above documentation (supplied with the card) is not altogether accurate. It seems that in reality the UART COM port selection jumpers (JP7 and JP8) have their definitions reversed. This means that for JP7, 1-2 selects COM3 while 2-3 selects COM1. For JP8, 1-2 selects COM4 while 2-3 selects COM2.

Note that this is what Andrew found with his card; different revisions may have fixed this minor glitch.

Conclusion and acknowledgements

As for the Prime3B-based cards, these cards, although obsolete, are very cheap to buy (often free) and are still quite handy if an extra printer port is required in a PC with ISA slots. If anyone has further information to add to this document, please email me (jwoithe at this domain).

Thanks are due to Andrew Su for providing much of the information contained in this page. I do not personally own a "Prime3B Mark II" card. Jonathan Woithe
29 March 2001