iffy EFE

so my EFE microcontroller board didnt quite work out from a couple weeks ago. various problems... the python onscreen visualization didnt run correctly, my capacitance values kept jumping around (leapfrog!), and i was bashing my head in on assembly syntax.

i tried the vinylcutter with the copper foil atop the epoxy substrate, but got a little frustrated at the weeding process. the cutting was fine; i think it was successful at around 65% force, and i had no problems with the sticky transfer. but weeding. argh! tweezers in hand, i would almost get there, and then near the end i'd rip up the leads. a tedious process that a spastic hand unfortunately doesnt have much patience for. i found solace and safety in the modella, which milled to perfection. ah.

some asm notes:

.equ actually assigns something another name (sort of like #DEFINE), aliasing, nom de plume, whatever you fancy
.def just declares a variable, taking dibs on a spot in memory
DDRM specifies whether a pin is output or input
sbi set bit - output
cbi clear bit - input
PORTB specifies whether a pin is turned high or low
sbi set bit - high
cbi clear bit - low

use undersampling to integrate the slow conversion rate of the A->D and the fast sample + hold signal. when your finger gets closer, the charge is slower because humans are huge capacitors. the big hint in running the EFE boards is to convert your object to capacitance and resistance.

also, the datasheet == ATtiny bible. read it and know.

postscript: for the jumps, neil suggests putting in NOPs to syncronize the ADC undersampling of 60-cycle. gotta figure this out.