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The Projects Forum Working on an electronics project and would like some suggestions, help or critiques? If you would like to comment or assist others with their projects, this is the place to do it.

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  #1  
Old 11-01-2011, 06:59 PM
newbieEm newbieEm is offline
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Default MMC interface to PIC18f4550

I have built a kit with PIC8F4550 on breadboard. I have couple of LEDS, LCD working. Now I have to attach a SD or MMC reader. I have seen the schematics but it seems too complicated. For example how about converting 5 volts to 3.3 volts (use a LED or resistance??) I need help with hardware design also which MMC card reader to buy (from sparksfun??). I am hardware newbie, software I can manage. Any help/suggestion/simple schematics/tools/parts listing would be appreciated. Thanks
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Old 11-02-2011, 12:26 AM
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THE_RB THE_RB is offline
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I would suggest you save yourselfd a ton of work and hassle and buy one of these for $19.90, it has the level conversion, 3.3v regulator, etc already built in;


http://www.mikroe.com/eng/products/v.../mmc-sd-board/
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Roman Black - PICs and electronics. Author of BTc PIC-sound encoder, Shift1-LCD project, the TalkBotBrain talking PIC controller, LiniStepper open-source microstepping motor driver, the Black Regulator 2-transistor SMPS, and probably some other stuff; www.RomanBlack.com
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Old 11-05-2011, 12:58 AM
upand_at_them upand_at_them is offline
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A simple voltage divider works fine. I've done it for SD/MMC card interfaces.
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Old 11-05-2011, 01:38 AM
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THE_RB THE_RB is offline
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Yeah, it can be made to work if you know how to do it and what to watch out for.

But the OP said he was looking at "buying a MMC card reader from sparkfun" so the one I linked to is not much different in price but has onboard 3.3v regulator and level converter ICs. And PIC source code examples etc supplied free of charge.
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Roman Black - PICs and electronics. Author of BTc PIC-sound encoder, Shift1-LCD project, the TalkBotBrain talking PIC controller, LiniStepper open-source microstepping motor driver, the Black Regulator 2-transistor SMPS, and probably some other stuff; www.RomanBlack.com
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