#avr Logs

Apr 02 2020

10:51 AM Fuchikoma: So I'm thinking I might abandon using an external MP3 player module for this project I've been working on for months now
10:57 AM Fuchikoma: And playing WAV files directly from the uC from some nonvolatile memory
10:57 AM Fuchikoma: Anyone have experience with that? Some handy references for example?
11:09 AM Fuchikoma: It looks like you just set up the PWM output hardware and take bytes from the WAV file to use a PWM values?
11:09 AM Fuchikoma: Updating the byte at apropriate intervals to get the correct bitrate
11:11 AM twnqx: assuming you a nice filter on the digital output, yes
11:13 AM cehteh: Fuchikoma: if you are at that, try to make PCM instead PWM .. would have better quality
11:14 AM cehteh: such is on my todo list as well
11:14 AM Fuchikoma: cehteh:Eh?
11:16 AM cehteh: yes you can do that
11:16 AM cehteh: https://en.wikipedia.org/wiki/Delta_modulation
11:17 AM cehteh: thus changing frequency not duty cycle at static frequency
11:17 AM Fuchikoma: Oh I meant PWM as in the PWM hardware of the AVR
11:17 AM cehteh: yes you can do that with the PWM hardware as well
11:18 AM cehteh: instead OCR for the duty you set OCR at some static small value (1 for example) but them modify the TOP / frequency
11:19 AM Fuchikoma: hrm
11:19 AM Fuchikoma: Worth considering
11:19 AM cehteh: its a but freaky on the math, but should be doable
11:19 AM Fuchikoma: The project is a talking clock, so it's not like quality is a major concern
11:22 AM cehteh: i didnt implemet that so far, but in theory it should be superior to PWM because your carrier frequnecy is much higher thus you can filter it better
11:23 AM Fuchikoma: https://www.youtube.com/watch?v=d60ybLqbDLg Haven't been keeping up with documenting progress; since this I've added volume control and time set functionality. I got hung up when the MP3 player module uses too much power to run well on 2xAA cells
11:25 AM Fuchikoma: Been stuck trying to cobble a boost converter but it's probably a lost cause, so plan B is to just get the Attiny85 to do it
04:49 PM markasoftware: uh howmuch power
04:50 PM markasoftware: i can't imagine an mp3 player that can't run on 2 double as
04:51 PM vmt: markasoftware: you mark7?
05:06 PM markasoftware: nah
11:17 PM day__ is now known as day