I don't remember if the SSP input is a schmitt trigger input or not, but
if it is, 80% of 5 would be 4V, which 3.3V does not meet. If it is not an
ST input, I guess it could be driven directly by 3.3V levels. The Maxim
chip is nice in that it handles level translation in both directions in
just one part. Voltage dividers could be used in one direction, but with
an increased part count (though probably lower cost). So... it's just the
way I chose to do it. If the SSP input will accept 3.3V levels, I guess
that'd be fine.

Thanks!

Harold


> Harold,
> any reason you're using a level translator instead of just using a voltage
> divider on the pic->sd lines and nothing on the sd->pic line (since 3.3V
> is
> high enough on a 5V pin)? I've seen both implementations and I'm wondering
> if there's a good reason for a level translator.
> Thanks,
> - Marcel
>
> On 7/15/06, Harold Hallikainen <harold@hallikainen.com> wrote:
>>
>> I just finished some C18 code that talks to MMC/SD cards. I'm reading
>> and
>> writing text files using FAT16. It can also format cards from 128M to
>> 1G.
>> I use an SPI interface to the card. I'm running the PIC at 5V and using
>> a
>> Maxim level translator to get to the 3 or 3.3V (I'm at home and don't
>> remember the exact voltage). The MMC/SD is pretty easy to talk to.
>> Digging
>> thru the details of FAT16 was fun. If needed, I may be able to send you
>> some code.
>>
>> Harold
>>
>>
>> > I am developing a PIC based project that will play MP3 sound effects
>> and
>> > music.
>> >   I have decided to use the STA013 MP3 decoder.
>> >   To simplify development, I want to store all of my MP3 files on an
>> SD
>> > card or CF card.
>> >   This would allow me to simply add and remove files with a PC and
>> Card
>> > reader.
>> >   When the card is plugged into my PIC circuit, the PIC will need to
>> read
>> > data from FAT encoded data files out of the SD or CF card. I would
>> > prefer to use the SD card since they are smaller and lighter
>> (important
>> > in my application). I am not sure if its tougher to interface a CF vs.
>> > SD card to a PIC18 series. I found the pinouts for the SD card,
>> however
>> > its not 100% clear how to interface to a PIC (additional interface
>> > circuity, pull up resistors, etc.). Another help would be to find some
>> > PIC drivers to read data from FAT files on these cards. Any direction
>> > would be helpfull.
>> >   Thanks
>> >
>> >
>> >
>> >
>> > ---------------------------------
>> > Yahoo! Music Unlimited - Access over 1 million songs.Try it free.
>> > --
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>>
>>
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