Max517

[hobiadami]

I'm working on a hobby project cyclocomputer for my upright bicycle at some nights after work.

It has a 128x64 graphical mono LCD,
several sensors from the pedals, wheel
A real time clock
Two temperature sensors
SD card socket
and a servo motor control for modifying the (mechanical) difficulty setting of the bicycle.

I'm using 18F458

I'm trying to implement a sound system as well for maybe creating some sound effects, playing voice messages or maybe simple tunes.

I'm using max517 DAC thru the I2C bus. The maximum frequency of a sinus generated with the chip is around 40hertz. For a simple sound system and telephone quality audio, i guess i need to be able to generate 3khz.

Instead of the max517 dac, I've tried the pwm output of PIC to generate sound yesterday. The maximum frequency achieved is around 6.5khz. but somehow the sound generated is not good. even doesn't sound like a sinus.

At work, in a demoboard 's sample code for an ARM7 based LPC2378, i've seen a USB speaker project for the PC. The code uses only the onboard DAC of the 2378 and when plugged in, runs as the loudspeaker of the PC.

I want my PIC project to generate similar sounds for years but so far i didn't manage

I didn't give up yet. Any recommendations?
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