RE: [ECOS] CF driver

[Gary Thomas <gthomas at cambridge dot redhat dot com>]

On 21-May-2001 Andrea Acquaviva wrote:
> Hi all,
> 
> I'm writing an eCos driver for the CF interface on my Strongarm 1100
> based board. I'm modifing the same driver written for the assabet board.
> The main difference is that the assabet driver uses the SA1110 to
> program the pcmcia interface, while on my board there is not the SA1110
> companion chip.
> 
> In the assabet driver the CF is programmed also by writing on the BCR
> register of the SA1110, in particular the interesting instruction is:
> 
>  assabet_BCR(SA1110_BCR_CF_POWER |
>                         SA1110_BCR_CF_RESET |
>                         SA1110_BCR_CF_BUS,
>                         SA1110_BCR_CF_POWER_ON |
>                         SA1110_BCR_CF_RESET_ENABLE |
>                         SA1110_BCR_CF_BUS_ON);
> 
> My question is: what's the mean of the SA1110_BCR_CF_BUS flag? Is it a
> particular assabet feature or do it perform some actions on the
> PCMCIA interface pins that I must be aware?

The interface on the SA1110 can be controlled by three different pins.

  Power - whether or not Vcc is applied to the bus
  Bus   - whether or not the bus drivers are enabled
  Reset - whether or not the device is in reset

Not all controllers allow for such fine control.  In many cases, the
power and bus controls are grouped together.