prepare a generator for the ino file that should make it easier to only include the code that is necessary to play with one particular hardware configuration
i can now generate c functions
more c generation, need to fix last comma in parameter list and reading parameters from stack
appart from the extraneous comma in arglists, the generated code looks pretty good now:
const int dac_chip_select_pin = 16;
F_DAC
value_t dac_init ()
{
  SPI.begin();
  SPI.setBitOrder(MSBFIRST);
  SPI.setDataMode(SPI_MODE2);
  pinMode(chipSelectPin, OUTPUT);
  analogReadResolution(12);
}
value_t dac_fun (unsigned short b,unsigned short a,)
{
  digitalWrite(dac_chip_select_pin, LOW);
  byte x,y,z;
  x = (0xff0 & a) >> 4;
  y = ((0xf & a) << 4) + ((0xf00 & b) >> 8);
  z = 0xff & b;
  SPI.transfer(x);
  SPI.transfer(y);
  SPI.transfer(z);
  digitalWrite(dac_chip_select_pin, HIGH);
  return T;
}
case F_DAC: {
  argcount(dac,nargs,2);
  v= dac(tonumber(Stack[SP-2],"dac"),tonumber(Stack[SP-1],"dac"),);
}  break;
start writing some documentation
try to read back the data i stored with missing newline.
also start implementing difference of camera images. perhaps this can be better compressed using gzip.
tried calculating the difference and compressing with gzip and xz
collect  Wire and SPI function defintions
allow different lisp and c-name for functions, add pin-mode
add analogRead and digitalWrite
delay delay-microseconds micros room