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IC: MiniVol PGA23xx control board


2007-03-24 7:54 am
Several months ago I got a request from theAnonymous1 to code up some firmware for controlling PGA2320. Being the nice guy that I am (and needing the code myself ;)), I finally got around to designing a board and getting prototypes done up. I've now received mine, built it up and got the firmware to a decent state. It's not fully complete yet (no rotary encoder support until I can get one), but definitely in a usable state.

If there's interest, I am willing to organize a group buy for PCBs and microcontrollers and flash the micros for anyone that doesn't have a programmer. Unless there are a large number of boards to be ordered, it would likely be about $10 including shipping for the PCBs and $3-5 for the microcontroller.

Board has inputs for either up/down switches or a rotary encoder, has a mute button input and mute LED. There are jumpers to cap the PGA23xx at 0dB gain (it can go up to +31.5dB without the cap), and to select whether a rotary encoder or pushbuttons are in use. It is 1.25" x 1.7" with two mounting holes. SMD parts are used throughout (including PGA23xx) except for the ATtiny24 microcontroller.

It's fairly easy to use this board for a balanced configuration with two boards and one microcontroller, but it does require a bit of a kludge to tap the SPI lines on the 'master' board (nothing hard).

More details are at http://audio.gotroot.ca/minivol/ (sorry IE users, I'm too lazy to support your browser :))


2007-03-24 7:54 am
guglielmope said:
In Italy is very hard to find the components.
What about a complete kit?
I don't think I have time to take on organizing a full kit buy, but there are really only two parts that I can see you having difficulty with; the microcontroller and PGA23xx chip. Everything else is standard passive parts. I can provide the microcontroller for you, so all you need to find is the PGA23xx. It should be available from DigiKey Italy, or you could sample it directly from TI.

I'm interested in 3-5 boards with preprogrammed controllers.


PS: Would this work instead of pushbuttons? Mouser P/N 105-SR10030-PS Then you could have rotary control and the mute button as well.
I believe this would work fine, but (at least currently, anyway) holding down the buttons doesn't ramp the volume, you need to press once per step, so it might not be any better for you. I may change this behaviour though. With the final firmware you'll be able to use a real rotary encoder though.

It would take about 50 boards requested to beat the rate I get on my prototypes and I don't see that happening, so I don't think a group buy is really worthwhile. If anyone is interested, I will be making another prototype order next week. If you want boards, contact me via e-mail and I will order however many you need.