Lpc2000

--- In lpc2000@yahoogroups.com, "douglasbolton" <doug@c...> wrote:
> Hi all
> 
> has anybody had any problems interfacing MMC cards to an LPCxx using 
> the SPI interface.
> 
> I've previously interfaced to HC11 and AVR without any problems. I 
> can get some cards to initialise, however some will consistently not 
> initialise with the LPC. I seem to be missing the LSB in the response 
> byte.
> 
> The cards which won't work with the LPCxx will work fine in my HC11 
> and AVR systems.
> 
> I've tried various bus speeds without success.
> 
> Doug

Hi Doug

I had the same effect with MMC/SD cards. Controllers from older
SANDISK cards and Toshiba work fine, while Hitachi controlled cards
fail. I even killed a SANDISK Ultra-SD card with the LPC. (These cards
are somtimes killed in Palms also, does anybody know why?)
All cards work on AVR,CPU32 and Palm. There must be a subtle
difference in SPI Timing! With an emulated SPI on the LPC all cards work !


For the wish list:

It would be a great improvment to have a faster and better SPI and
much faster GPIO to emulate peripherals.

What I also miss is the possibility to dynamically switch the clocks
for better power mangament. (like newer blackfins or mps430)

For this you would need a pclk bypass bit for each peripheral to get a
perpherals clock from the master (crystal) clock without pll.

This would ensure stable timers and uarts while switching pll, cclk
and pclk  to whatever value.

gerhard