Re: Corrections re: PCMCIA/PC Card/CardBus/PCI/etc.

From: Erik Walthinsen (
Date: 2002-03-15 11:29:08 UTC

On Fri, 2002-03-15 at 01:02, Eric Johanson wrote:
> I've been bitten by the voltage issue before; DWL-650 cards don't work in
> most cardbus slots, due to them being 16bit, 3.3 volt. It was rumored
> that the dlink cards had in fact been 32bit only, but some research into
> the chipsets (Overheard at wireless meet, YMMV) uncovered the fact that
> they are only 16 bit.

What I've read on the ptp wiki is that the card is indeed a 5v card, it just has a bad CIS tuple in it that confuses the cardmgr. There's a node in the wiki explaining the workaround, something like adding ignore_vcc_cis or somesuch. That will make the card work in any 5v PCMCIA slot. ( is unreachable for me atm or I'd have a link, the node is something like 'Dwl650Comments')

> I'm quite sure that the 'Ricoh Co Ltd RL5c475' is in fact a 32 bit
> 'cardbus' adaptor - I used a 32bit 5v scsi card (I don't recall
> the model) in a ricoh bridge, and it worked fine. The same card failed
> to function on a 16bit 5v notebook (old toshiba). I've also had Lucent
> Silvie (16bit, 5v) cards work under the ricoh bridges.
The Ricoh *chip* is indeed CardBus, like almost every other PCI-based chip except the PLX9052 used in some adapters. However, the board that ships with the DWL-650 (the one in question) is definitely a PCMCIA 16-bit 5v only card. Just like the PCI1410-based card we have that isn't actually CardBus, having only 5v and being keyed appropriately. If your CardBus cards work in the board you have, then you have a (somewhat rare) *real* CardBus adapter.

There are a couple reasons why they might castrate an otherwise perfectly usable chip like the RL5c475 or PCI1410:

  1. fractionally cheaper slots
  2. no voltage regulator (rl5c475) or TSP2211 voltage switch (PCI1410)
  3. vendor lock-in ("Only works with our XYZ card!")

This doesn't at all account for the astronomical price of actual CardBus adapters, as the incremental cost for the slot might be a dollar and the bits to switch the voltages as required maybe another dollar. Even tripling that as is commonplace does not account for $140 CardBus adapters. Someone should be shot, IMO.

      Erik Walthinsen <> - System Administrator
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