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Sat May 15 17:52:49 EDT 2010

Broken PAIA Fatman

I have two Fatman kits, one built but broken (probably uC died trough
short-circuit) and one not assembled.  Plan: order a desktop case for
the packaged kit + try to get the built one working with a PIC
controller.

DAC = floating point: note select uC P36 and P34-P35 for octave
select.

Trying 13.5 MHz xtal with 4550.  This won't work with fixed frequency
96 MHZ PLL, which needs a 4MHz input.  FIXED: using 8MHz XTAL.

4550 OK @ 230400 baud.

Next: Fatman power supply.  Done.  12V AC connected, and the
oscillators seem to work.

Next: envelopes.  

Both A(S)R for VCF and ADSR for VCA are on when inputs = 0V, which is
the reason it sounds when the pins are not driven; they go to NPN
base.

PIC pinouts

reserved:
- serial comm
- PWM
- analog in
- 1 interrupt for serial




envelope:
- 3 OUT
- 2 IN (envelope interrupt)

CV:
- 12 OUT: 8 (NOTE) + 2 (OCTAVE) + 2 (S/H)
- 74HC373 can be patched through (use SH for setting CVs)


PIN allot

- RB7,6,5 as inputs for 2x envelope in and 1x midi in.
  MIDI @ 38400 baud / 12MIPS is DIV=312.5

- RA0,1,6 as outputs for envelopes.



next: A(S)R input  : O15 (P31)  -> RA4 (P6)
works, after fixing the +8 volt connection




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