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Post by Dingo on Jul 26, 2004 9:22:02 GMT 10
What does anyone recommend for a ic chip to playback simple songs and beeps etc?
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Post by Thrashbarg on Aug 10, 2004 16:28:44 GMT 10
The simplest method I can think of is an EEPROM with a resistor network attached to the 8-bit output to form a simple A/D converter. w1.859.telia.com/~u85920178/eprom/epromosc.htmI'd use the Flash EEPROMs from old motherboards to store data. EPROMs can be used but they need those damn expensive UV erasure boxes. |
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Post by Dingo on Aug 10, 2004 16:48:26 GMT 10
Excellent link. Just the info I was looking for!
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Post by ZapBrannigan on Aug 10, 2004 17:48:18 GMT 10
The first half of that circuit acts as frequency control and the second is a D-A of a stored sine wave... A more sophisticated way to do it could be to control the timing through a micro. That micro could have certain notes' frequencys stored in a look up table. That frequency is how quickly the address to output from the EEPROM cycles from 0 -> sample length and back around again. If you then had in another storage bank a series of notes and the length of the note, you could get yourself a basic MIDI system happening, with fully customizable music, based on the notes and periods that you access  ie Micro grabs note and length from ROM. Converts note into a frequency. Uses frequency to control a timer which clocks a counter whose output is the address to output from the EEPROM containing the sine wave. Keep on clocking the EEPROM at that speed for the length of another timer determined by the length of the note. There are better ways of doing it I am sure, but I think that it could work. |
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