Nerdy Texts of Analog and Embedded Systems Wizardry

Prototype B is up and running–
MicroSD, well, fits at least and the card-detect switch works:

The enclosure getting tapped:

And the pretty views of the done project:

I’ve found at least two dumb problems so far. The Audio In/Out jacks were interchanged in the harness, and the clock select switch was in the wrong place in line for the pulse shaper (only the RC oscillator was getting its pulses shaped before heading to the IRQ pin). Also I cannot seem to find a screw that is meant to mate with those MIDI jack mounting holes. There’s probably more that’s wrong. Once I am sure I’ve found all the bogeymen, I can pull the trigger on the final PCB order.
The uSD card is already being a bitch.
Holler,
TB

So the boards got here for the next (and hopefully last) prototype of the WTPA2.

Some exciting changes from the last proto — I not only fixed some dumb hardware bugs and changed some layouts to make more sense, but I added the pulse shaping circuit from the last post and…
Added a Micro SD card interface!

Again I really owe Olivier over at Mutable Instruments for this, since he once again shamed me out of my sloven embedded ways. Basically I didn’t want to have to deal with the SD spec (I did a little coding on MMC interfaces for the toy world and it sucked) and so I’d made the earlier daughterboard using a cheap SST flash IC. The flash IC was easy to deal with, but was admittedly a cop out. Olivier clowned me about this until I was embarrassed enough to change my ways. Users like removable memory, and a micro SD card provides 2GB of memory for about a dollar (as opposed to my 8MB before). So I sucked it up and made this board. It will be available for sale as a daughterboard (it’s deeply SMT) although I may swear a lot getting the new interface done.

Here’s the main board populated. And here’s the new Jack PCB added on: