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Maddman7887
Joined: 07 Jun 2010 Posts: 2
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PIC32 |
Posted: Sat Jun 12, 2010 11:20 pm |
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Power with 5v and SD card
Last edited by Maddman7887 on Thu Apr 24, 2014 7:04 am; edited 2 times in total |
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Ttelmah
Joined: 11 Mar 2010 Posts: 19360
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Posted: Sun Jun 13, 2010 3:07 am |
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The first thing you are going to need to do, is sort out the hardware.....
If you are connecting directly to a 5v PIC, then you will almost certainly overvoltage the device. The PIC logic outputs can deliver more current than this chip needs as a supply. When the clock and data lines go 'high', these will be pulling up to well above the chips supply voltage. This will result in the supply level for the chip rising, and possible damage. You need resistive voltage dividers on the data lines from the PIC.
Then the data output from the chip, will also need to be buffered to bring the signal 'up' to a level that the PIC can read.
The supply at the chip needs smoothing.
Do a search here for people reading/writing SD cards. This is basically the core 'chip' used in some of these, and with only small modifications, the same code (and buffering...) is needed.
Best Wishes |
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Maddman7887
Joined: 07 Jun 2010 Posts: 2
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Posted: Mon Jun 14, 2010 4:23 pm |
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..........
Last edited by Maddman7887 on Thu Apr 24, 2014 6:52 am; edited 1 time in total |
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ckielstra
Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands
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Posted: Mon Jun 14, 2010 6:44 pm |
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Maddman7887 wrote: | The information you provided for me is Vague. I would need some more insight please. | Simple words:
Your PIC is running 5V. Yes?
The Atmel Dataflash is running at about 2.0 - 2.5V
Because the chips are not at the same voltage they can not talk to each other. Maybe you have damaged the Dataflash.
Solution 1: choose a newer PIC type that can run at the same 2.5V. A new PIC is also cheaper than the old PIC16F877A.
Solution 2: implement 'interface' electronics. Difficult. Lots of problems. More expensive than a new PIC. |
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