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Ethernet card forced to 8 Bit mode??

ibmapc

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Apr 5, 2010
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Albany, OR USA
I have a generic 486DX2 66 system with an Intel Etherexpress 8/16 ethernet adapter plugged into a 16 bit ISA slot. Last night, I was reviewing the setting using SoftSet and noticed it was set to "Force 8 bit mode". Upon further investigation, it does that when used in a system with greater than 12mhz buss(if I remember correctly the buss on this system runs at 33mhz). So I guess I need a faster card. Any sugestions? Does the 3Com Etherlink III run in 16 bit mode on a 33mhz bus?
 
I had a similar problem years and years ago on my old Dell 486, never did find a solution. Ended up replacing it with an Intel Pro 100 Isa adapter. That card is still in the machine today. :)


As for the Etherlink III, I know the pci version does indeed run on 33mhz bus, not so sure about the isa rev though...

I am a little confused though, doesnt isa have a cap of 16/20mhz, normally running at like 8mhz? Bit rusty, but could have sworn 33mhz was solely vlb/pci/mca.
 
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The ISA bus on your 486 machine runs around 8Mhz, it is clocked separate from the CPU bus on 486 machines. The card shouldn't have a problem.
 
The ISA bus on your 486 machine runs around 8Mhz, it is clocked separate from the CPU bus on 486 machines. The card shouldn't have a problem.

Are you sure about that 8mhz? No matter how I set the board, it goes back to "Force 8 bit mode".

check out this Wikipedia article

There is a jumper setting on my motherboard which sets the buss speed to > 33MHz (for a 486DX 50)or <= 33MHz which is needed for the DX2 66. That could be for the VLB slots. At any rate, the board will not run in 16 bit mode in this system.
 
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In the manuals of some PCI/ISA motherboards, one sees reference to dividing the PCI clock by 4 to get the ISA clock (e.g. 33 MHz / 4 = 8.25 MHz).
 
There is a jumper setting on my motherboard which sets the buss speed to > 33MHz (for a 486DX 50)or <= 33MHz which is needed for the DX2 66. That could be for the VLB slots. At any rate, the board will not run in 16 bit mode in this system.

Thats for the VLB slots, which are the only slots in the system that directly run at the CPU's bus speed (in your case 33Mhz).
 
Ok, looks like the problem is NOT the bus speed. The change only happens after Windows 3.11 is started. So @#$%ing Windows is changing the mode to 8 bit for some reason. Could it be that Windows is detecting a conflict with my video card(Diamond Speedstar Pro VLB)? Any Ideas?
 
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