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Music servers and other computer based digital audio technologies.

RE: I disagree with you and agree with Sprezza Tura

I'm not familiar with the instruction set of the 8051, but I am familiar with the similar 6502, which was the processor in the Apple II personal computer. I even programmed it to do digital signal processing (LPC compression of telephone quality voice), and this worked after a fashion, but the processing ran at 10 times slower than real time after I speeded up my original Basic code by changing the data encoding, rewriting the math library routines and doing all the processing in assembler. The 64 kb RAM allowed storage of only a few seconds of voice. My friends and I built a sound card out of a free sample 64 kb Motorola CODEC chip. This was around 1980. I also made the Apple II speaker (connected to a programmable flip-flop) play a mix of square waves of two different frequencies by using pulse density modulation.

While the SD card runs in one clock domain, I'd be surprised if the number of clock cycles required per data transfer is fixed. I'm certain that is not the case when it comes to writes, which can become very slow, particularly if the card has a lot of wear from many writes. I use one of these SD cards with my Raspberry Pi, and I have gone through about six cards in 18 months due to wear-out, from doing system updates, etc..



Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar


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