My partner (and electrical engineer and bare metal guru) and I (an experienced programmer and data center designer) have a (Wheezy) project, several months in the pipeline, using an RPi(B) that in the end needs simply needs to output stronger audio. We've amped the PWM 3.5mm, and for some situations, that's adequate. We also have a version that uses a usb dongle (109/related) out, with some improvement in quality and RMS, and that's working for some installations.
But for some interfaces, it's just not a strong enough output. My partner just built an add on board with an NTE823 and enough gadetry to drive 8 or 600 ohms with apparently adequate p2p to it.
This addon-board, which is functional in testing, is intended to be driven by (Alt5) PWM0 (delivering an ALSA/mpg321 out) signal via GPIO18 (pin 12). Problem is I'm not getting that to happen yet, and would like some advice as to which way to go for 44KHz pwm audio. I've tried wiringPi, #bin/sh ...export (which just looks inevitably too slow), and am about to try python.GPIO, but need to focus on a direction that can possibly succeed. I need to accomplish this prior to a series of surgeries I begin late next week.
Anyone actually driven (single chan) audio out that way? I'll take the 11 bit quality in this case, but any dramatic deviations from the complex streaming, scheduling, self-monitoring set of php, c ,python,shell commands and installed packages for both audio and timed external comm that this unit have finally flawlessly came together, are out.
Any pointers, suggestions of directions, flat out statements of fact? (or even help?) I have searched this more than any single topic in recent memory, so it's not that I don't know how to use the search button. Our problem is we have found the hole in our complimentary skills - he can't program other than deep metal, and I am seeing a this I/O assignment class of knowledge as one I don't yet have. I'm not incapable of learning, but I would appreciate anyone who knows which one of these GPIO access options works for the task listed, to narrow the scope of what I need to learn and do.Thanks.
