fab-step-log.md

#include "homing.h"
#include "drivers/step_a4950.h"

endpoint_t* _homeStateEP;
uint8_t homeState = HOMESTATE_NONE;
uint32_t homeBackoffStepsTaken = 0;

// home settings
boolean homeDir = true;
unsigned long lastHomeOperation = 0;
unsigned long homeOperationPeriod = 1000; // in us
uint32_t homeBackoffDistance = 100;

void homeSetup(endpoint_t* homeStateEP){
    // stash this
    _homeStateEP = homeStateEP;
    // make an input
    PORT->Group[LIMIT_PORT].DIRCLR.reg = (1 << LIMIT_PIN);
    PORT->Group[LIMIT_PORT].PINCFG[LIMIT_PIN].bit.INEN = 1;
    // pullup
    PORT->Group[LIMIT_PORT].OUTSET.reg = (1 << LIMIT_PIN);
}

// return true if limit switch is hit
boolean limitHit(void){
    return (PORT->Group[LIMIT_PORT].IN.reg & (1 << LIMIT_PIN));
}

void writeHomeSettings(boolean dir, uint32_t stepsPerSecond, uint32_t offset){
    homeDir = dir;
    homeOperationPeriod = 1000000 / stepsPerSecond;
    homeBackoffDistance = offset;
}

uint8_t getHomeState(void){
    return homeState;
}

void startHomingRoutine(void){
    homeState = HOMESTATE_APPROACH;
    endpointWrite(_homeStateEP, &homeState, 1);
}

void runHomingRoutine(void){
  // run this at a rate...
  if(lastHomeOperation + homeOperationPeriod > micros()) return;
  lastHomeOperation = micros();
  // state switch;
  switch(homeState){
    case HOMESTATE_NONE:
      break;
    case HOMESTATE_APPROACH:
      // check for contact,
      if(limitHit()){
        homeState = HOMESTATE_BACKOFF;
        endpointWrite(_homeStateEP, &homeState, 1);
        homeBackoffStepsTaken = 0;
      } else {
        step_a4950_dir(homeDir);
        step_a4950_step();
      }
      break;
    case HOMESTATE_BACKOFF:
      step_a4950_dir(!homeDir);
      step_a4950_step();
      homeBackoffStepsTaken ++;
      if(homeBackoffStepsTaken > homeBackoffDistance){
        homeState = HOMESTATE_NONE;
        endpointWrite(_homeStateEP, &homeState, 1);
      }
      break;
    default:
      // broken,
      homeState = HOMESTATE_NONE;
      endpointWrite(_homeStateEP, &homeState, 1);
      break;
  }
}