On Tuesday, June 5, 2001, at 04:39 AM, Leonard Ye wrote:
> However, we would like to remove Neponset board to cut the cost. In
> the "Intel StrongARM SA1110 Microprocessor Advanced Developer's Manual"
> Page 10-60, an external logic circuit is given to interface a PCMCIA
> socket directly to SA1110 chip, i.e. bypassing the SA1111 companion
> chip. Had anyone successful modified the existing ARM linux
> distribution to support this circuit? Or any suggestions?
Actually, the very first version of PCMCIA Card Services for StrongARM
was written for an SA-1100 device which used logic similar to what you
see in the SA-1110 manual. Note that much of this logic is transparent
to software, but there are a few things which the kernel may need to
know about (depending on what kinds of cards you plan to use):
- Card Detect (must be interruptible)
- Card Ready
- Card Reset
- Card Voltage Sense
- Card Battery Voltage Detect
- Card Write Protect
Chances are you'll hook some or all of these up to GPIOs. Note that you
also have to account for some sort of power switching network to route
3.3V or 5V to the card (possibly even 12V Vpp).
Once you've decided on how the control and status signals will be routed
to the StrongARM, it's a simple matter of reflecting these decisions in
a thin layer of the SA-1100 PCMCIA driver. You'll see examples for
Assabet, Neponset, Bitsy, and others already in the kernel source. Study
them to see what actions they take based on stimuli from the
higher-level driver; it should be clear what your version needs to do.
-jd
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