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POPWM Audio with reading data from SD card
 

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  1. POPWM Audio with reading data from SD card
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    <p>Currently I'm working on this Arduino/Nanode project where we want to play a collection of WAV-files stored on a SD-card, with PWM on clock OCR0. - I'm able to play the PWM perfectly, starting from the sketch from Michael Smith on the Arduino website: <a href="http://www.arduino.cc/playground/Code/PCMAudio" rel="nofollow noreferrer">http://www.arduino.cc/playground/Code/PCMAudio</a> - I'm able to read the SD-card correctly and convert the data to 8bit integers that look correct when I print them to the serial window.</p> <p>The problem I have is when I feed in these integers to the PWM value of the clock.<br> As I said, when I'm using the original PWM Audio file with my own WAV-file converted to a .h-file (through wav2c) it works and it sounds good. When I'm reading the SD-card it shows me the correct values. It shows correct when I'm reading the WAV-files direct and also (what I'm trying in my latest version posted here) as I convert them to text-files and read these. When I'm feeding in the integers from the text file, I hear a horn-like sound, like if the PWM uses the wrong values to output.</p> <p>I'm guessing the problem is somewhere in the casting of the data into the byte data the Atmega uses. But I don't have any clue where to look or how to solve it. I noticed that the original file uses unsigned char's where I'm using uint_t8. I tried to cast them but it's not working.</p> <p>Does anyone has some experience in this? Or any clue how I could possible solve this?</p> <p>Many thanks for you help and time!</p> <p>Jeroen</p> <p>PS: Below is the piece of my code where I read through the text files and convert them to integers. They always consist of 3 characters; value 21 for example is printed as 021 in the file, and seperated with a comma which the script skips with the 4th myFile.read()</p> <pre><code>myFile = SD.open(FileName); char sampleTMP[4]; sampleTMP[0] = (myFile.read()); sampleTMP[1] = (myFile.read()); sampleTMP[2] = (myFile.read()); sampleTMP[3] = 0; myFile.read(); unsigned char ss; ss = atoi(sampleTMP); Serial.println(ss, DEC); OCR0A = ss; OCR0B = ss; </code></pre>
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