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Topic: New library for PWM playback from SD cards: SimpleSDAudio (Read 45 times) previous topic - next topic

Tuttut

Hi, I looked over the Gizdino+ schematic: It runs on 5V, so you need level-shifters and you should test the 3v3 pin before with a multimeter to ensure that at least there is 3.3v. Second, the gizdino+-thing has sanguino pinmap, but datasheet says that there is a mapping for arduino-compatibility. Whatever, in the end you must ensure that the hardware spi pins are connected correctly to the card, so mosi to mosi, miso to miso, clk to clk and cs to pin 4 - but i dont know if in arduino or sanguino or gizdino numbering. Even if that is all correct i dont know if it will work because that clone is not very compatible to arduino. better go for the real one - at least take one with the correct cpu. the gizdino-non-plus version may work, but beware - the statement that it is 3.3v seems to be a bad typo to me...

xl97


My board has a 5V and 3.3 V.

I directly connected the MOSI, MISO, and SCK of the SD card to the MOSI, MISO, and SCK of my arduino.
I also directly connected the VCC pin of my SD card to the 3.3V of the arduino.
After connecting everything, I checked the voltage at the 3.3V pin of my arduino.
I used a fluke to measure the voltage. I got a reading of 4.3 volts.

I'll try the 100uF. It might work.
Also, I'll try connecting the audio out to pin 9.


I believe you are referring to the outputs/pins....

but this does NOT mean your board runs on +3.3v logic level..

example the Arduino UNO has +5v & +3.3v output pins....

however the boards runs on +5v logic...  (even though there is a regulator outputting +3.3v on a pin or two)



I have tested/used this library on custom boards, Uno/Duemilanove (+5v)..  and even minimal Arduino circuits running on +3v, 8Mhz internal clock  (ie: no crystal no caps..etc)


First thing is to get an SD shield that properly works with your set-up..




meowth08

#132
Feb 22, 2013, 08:55 pm Last Edit: Feb 22, 2013, 09:07 pm by meowth08 Reason: 1
Hi,

Thanks for the replies.
I had a little experiment that may help you help me.
I measured SCK of SD car to gnd: 0V
MOSI = 4.4V
MISO = 5V
CS = 5V

Added later: I guess this already shows the error on interfacing.
Do you think this http://www.sparkfun.com/tutorials/65 can already correct the error?

Tuttut

Hi,
is it so hard to believe that your board is running on 5V and not on 3.3V even that #*&! website says something different? That you measured the 3.3V line at 4.2V is a sign that your SD card is fighting a deathly battle against the 5V. What happens is the following: The SD card is connected to 3.3V at VCC, but at 5V at one of the other pins. An internal protection diode in the card tries to clamp the excess voltage at the pin with 5V to the 3.3V supply, but that supply is also weak because the crapduino uses some 3.3V from the USB-seriell-converter chip instead of a powerful extra regulator. This way the 3.3V regulator looses the battle and its output voltage rises to 5V minus the typical diode foreward-voltage of 0.7-0.8V = 4.2V. This is not how it should be done! You can destroy your AVR, the USB-Seriell-Converter or the SD card. I don't know how long this battle can take place and who will win, but you might have already broken something. Hint: Try if your SD card still works within a PC before spending more time frying stuff...

Believe it: YOU NEED LEVEL-SHIFTERS or a SD-shield that has those!

meowth08

The SD card is still working.
It still contains the DING, DONG, and EXAMPLE.

I will then construct the "DIODE" from this site.
http://www.sparkfun.com/tutorials/65

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