Posted on January 12, 2007 at 09:25Hi,
On a current design I've been working on we've put a
MMC/SD card slot on-board with a view to logging to it.
The limitation I'm up against is that the ST7 itself
wouldn't handle a 512K byte sector in it's own memory
so the aim was to use a eeprom memory chip to work as
an intermediary. However, because they're both on the
SPI bus does this mean that comms with the MMC card
would be 'reset' as a result of switching to the memory
(i.e. dropping the chip select line)?
Technically after erasing a sector then writing smaller
bits at a time should work as can you start writing anywhere
within the sector so not to over-write anything?
As anyone had any joy with such an approach?
The same is true of the USB. Using low-speed I should be
able to request and send data through the ST7 to a PC from
the card. As this will be done in smaller blocks then
I can't see a problem with this as I'd only be reading.
Regards,
Mark
