[Xenomai-help] using a pcmcia parallel port card

[Xenomai-help] using a pcmcia parallel port card

[Theo Veenker]

Hi,

I'm trying to access a pcmcia parallel port (Trans Digital TDC303)
from a kernel space module. When I insert the card into the laptop
pcmcia_cs recognizes it and reports I/O address 0x3378. I tried
to access the device at that address like you would access LPT1
at 0x378. That didn't work; I assume the card is not actually at
that address or not enabled or something.

Does anyone have a clue how to use a pcmcia parallel port card
with xenomai (or any other pcmcia card for that matter)?

Thanks,
Theo

Re: [Xenomai-help] using a pcmcia parallel port card

[Gilles Chanteperdrix]

Theo Veenker wrote:
> Hi,
> 
> I'm trying to access a pcmcia parallel port (Trans Digital TDC303)
> from a kernel space module. When I insert the card into the laptop
> pcmcia_cs recognizes it and reports I/O address 0x3378. I tried
> to access the device at that address like you would access LPT1
> at 0x378. That didn't work; I assume the card is not actually at
> that address or not enabled or something.
> 
> Does anyone have a clue how to use a pcmcia parallel port card
> with xenomai (or any other pcmcia card for that matter)?

I would think your problem is not the pcmcia card (after all, nowadays,
a pcmcia driver is probably just a special kind of pci driver), your
problem is likely that you try to access this PCMCIA parallel port as if
it was the classical builtin ISA based parallel port, and it is not.
Does linux use the same driver for this parallel port as for the vanilla
parallel port ?

-- 
					    Gilles.

Re: [Xenomai-help] using a pcmcia parallel port card

[Theo Veenker]

Gilles Chanteperdrix wrote:
> Theo Veenker wrote:
>> Hi,
>>
>> I'm trying to access a pcmcia parallel port (Trans Digital TDC303)
>> from a kernel space module. When I insert the card into the laptop
>> pcmcia_cs recognizes it and reports I/O address 0x3378. I tried
>> to access the device at that address like you would access LPT1
>> at 0x378. That didn't work; I assume the card is not actually at
>> that address or not enabled or something.
>>
>> Does anyone have a clue how to use a pcmcia parallel port card
>> with xenomai (or any other pcmcia card for that matter)?
> 
> I would think your problem is not the pcmcia card (after all, nowadays,
> a pcmcia driver is probably just a special kind of pci driver), your
> problem is likely that you try to access this PCMCIA parallel port as if
> it was the classical builtin ISA based parallel port, and it is not.
> Does linux use the same driver for this parallel port as for the vanilla
> parallel port ?
> 

Thanks. So modern PC cards are not ISA like?

I believe the vanilla port requires parport or parport_pc (a guess, I
never used this) and the particular pcmcia card I have is handled by
parport_cs (also handles the similar Quatech SPP-100).

Meanwhile I investigated a little further and found out by peeking at
the target I/O address (0x3378) and above/below, that the card is indeed
visible at that address. When card not inserted I see 0xFF, when inserted
I see data looking similar to what I see at 0x378. Maybe you are right
and the device cannot be accessed this way; in that case I hope someone
can hint me where to go. But first I'm going to try to find out if the
device isn't simply in the wrong mode (mode other than SPP). I'll let
you know.

Theo

Re: [Xenomai-help] using a pcmcia parallel port card

[Theo Veenker]

Veenker, Theo wrote:
> 
> 
> Gilles Chanteperdrix wrote:
>  > Theo Veenker wrote:
>  >> Hi,
>  >>
>  >> I'm trying to access a pcmcia parallel port (Trans Digital TDC303)
>  >> from a kernel space module. When I insert the card into the laptop
>  >> pcmcia_cs recognizes it and reports I/O address 0x3378. I tried
>  >> to access the device at that address like you would access LPT1
>  >> at 0x378. That didn't work; I assume the card is not actually at
>  >> that address or not enabled or something.
>  >>
>  >> Does anyone have a clue how to use a pcmcia parallel port card
>  >> with xenomai (or any other pcmcia card for that matter)?
>  >
>  > I would think your problem is not the pcmcia card (after all, nowadays,
>  > a pcmcia driver is probably just a special kind of pci driver), your
>  > problem is likely that you try to access this PCMCIA parallel port as if
>  > it was the classical builtin ISA based parallel port, and it is not.
>  > Does linux use the same driver for this parallel port as for the vanilla
>  > parallel port ?
>  >
> 
> Thanks. So modern PC cards are not ISA like?
> 
> I believe the vanilla port requires parport or parport_pc (a guess, I
> never used this) and the particular pcmcia card I have is handled by
> parport_cs (also handles the similar Quatech SPP-100).
> 
> Meanwhile I investigated a little further and found out by peeking at
> the target I/O address (0x3378) and above/below, that the card is indeed
> visible at that address. When card not inserted I see 0xFF, when inserted
> I see data looking similar to what I see at 0x378. Maybe you are right
> and the device cannot be accessed this way; in that case I hope someone
> can hint me where to go. But first I'm going to try to find out if the
> device isn't simply in the wrong mode (mode other than SPP). I'll let
> you know.

I'm glad to say from a linux test program I can access this pcmcia card
just like the regular parallel port. Apparently the card doesn't have
internal pull-ups on the status lines (like the regular port does) so
my switches to ground connected to the status lines had little effect.
Adding external pull-ups fixed that.

Theo

Re: [Xenomai-help] using a pcmcia parallel port card

[Gilles Chanteperdrix]

Theo Veenker wrote:
> I'm glad to say from a linux test program I can access this pcmcia card
> just like the regular parallel port. Apparently the card doesn't have
> internal pull-ups on the status lines (like the regular port does) so
> my switches to ground connected to the status lines had little effect.
> Adding external pull-ups fixed that.

Well, it was just a wild guess... Sorry for the noise.

-- 
                                                 Gilles.