Hi Ambrogio,
Page 10, Figure 2 is a really simple bi-directional level shifter for 3.3V to 5V systems.
http://www.standardics.nxp.com/suppo...df/an97055.pdf
If you have a couple BS170 or similar on-hand, this one works, and it's cheap.
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Hi Ambrogio,
Page 10, Figure 2 is a really simple bi-directional level shifter for 3.3V to 5V systems.
http://www.standardics.nxp.com/suppo...df/an97055.pdf
If you have a couple BS170 or similar on-hand, this one works, and it's cheap.
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Bruce,
it is a clever and inxpensive system.
If I am not wrong, I do have to put the level shifter from the data out of the card ( pin 7 ) to the input of PIC (pin 23) that has a higher VinH because of the S/T input type. It is more than 3v3.
I will have the BS170 by monday evening.
Additional question: where can i found the MMC digital interface declaration ?
I will like to examine a time history diagram from which I will learn to do with simple instruction ...
> when the SS has to be set hi or lo?
> same thing for SI, SO, CLK and so on . At the moment I am not able to find those kind of information .Those data are normally declared for all type of IC's I used up to now : where are the mmc interface data history ?
Thanks very much
Ambrogio
North Italy
Originally Posted by Bruce
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I'm not 100% sure if this what you're looking for, but Jan Axelson has a book titled
USB Mass Storage that covers MMC & SD cards.
http://www.lvr.com/usbmstoc.htm
Scroll down the page for a list.
You might also want to signup at http://www.jedec.org if you're looking for manuals, docs,
etc.
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Hi to all in the forum ,
Before starting with the hardware changes, I try with a program found on the web. I modified it for my hardware and it seem to me it is at least initializing the MMC properly.
The program is : MMC_POST[1] from Gary Warner. The modified one is attached. you can also find attached the terminal screen capture.
My system does not have the external EEPROM so i think this is the reason for which it does not go on...
I think it was not an hardware problem : >> What do you think ?
I will modify the program to avoid external EEPROM to see if it goes on.
Any comment ?
Thanks
Bye
Ambrogio
North Italy
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