Prime 3B (Mark II) based MultiIO card details

Introduction

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:

1x LGS-9547
1x LGS-9540
2x LGS-9633 (20-pin dip)

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

Two fast UARTs (16550 serial ports)
Serial port IRQ selectable (IRQ 3,4,5,7,10,11,12,13,14,15)
One enhanced printer port (SPP/ECP/EPP)
Printer port transfer rate up to 2MB/s
One enhanced IDE controller (connect up to two E-IDE/CDROM drives)
One floppy drive controller (connect up to two floppy drives)
Standard games port

Connector description

CON1: Game port connector
CON2: IDE harddisk connector
CON3: Harddisk in use LED
CON4: Floppy drive connector
CON5: UART1 (COM1/COM3) connector
CON6: UART2 (COM2/COM4) connector
CON7: LPT connector

Port addresses

UART1: COM1 at 0x3F8 or COM3 at 0x3E8
UART2: COM2 at 0x2F8 or COM4 at 0x2E8
Printer: LPT1 at 0x378 or LPT2 at 0x278

Jumper settings

JP1: IDE port enable/disable
1-2 = enable
2-3 = disable
JP2: Floppy disk controller enable/disable
1-2 = enable
2-3 = disable
JP3: UART1 enable/disable
1-2 = enable
2-3 = disable
JP4: UART2 enable/disable
1-2 = enable
2-3 = disable
JP7: UART1 port address
1-2 = 0x3F8 (COM1)
2-3 = 0x3E8 (COM3)
JP8: UART2 port address
1-2 = 0x2F8 (COM2)
2-3 = 0x2E8 (COM4)
JP9: Floppy controller address
1-2 = Primary
2-3 = Secondary
JP10: IDE port address
1-2 = Primary
2-3 = Secondary
JP11: Printer port select
1-2 = LPT2
2-3 = LPT3
JP12: Game port enable/disable
1-2 = enable
2-3 = disable
JP16: Floppy disk DRQ
1-2 = DRQ 1
2-3 = DRQ 3 (com3)
JP17: Floppy disk DACK
1-2 = DACK 1
2-3 = DACK 3
JP18: IOCHKDY enable/disable
Closed = enable
Open = disable

JP5 and JP6 select the printer port mode:

JP5 1-2, JP6 1-2: Unidirectional
JP5 2-3, JP6 1-2: ECP mode
JP5 1-2, JP6 2-3: EPP mode
JP5 2-3, JP6 2-3: PIO mode disabled

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