added test firmware to set up drv8825

nrf52-stepper/nrf52-drv8825/nrf52-drv8825.ino

+
+uint16_t pwms[1] = {0};
+
+const uint8_t pin_mode1 = 3; //A1
+const uint8_t pin_mode0 = 0; //XL1
+const uint8_t pin_step = 1; //XL2
+const uint8_t pin_direction = 2; //A0
+const uint8_t pin_nrst = 27; //p27
+const uint8_t pin_ref = 26; //p26
+
+
+
+void setup() {
+
+  Serial.begin(115200);
+  NRF_GPIO->DIRSET = (1 << pin_nrst); //set nrst/nslp pins as output
+  NRF_GPIO->OUTCLR = (1 << pin_nrst); //set nrst/nslp low to disable drv8825
+  NRF_GPIO->OUT = (0<<pin_nrst);
+  
+  //Switch to internal LFCLK to disconnect from XL1 and XL2
+  NRF_CLOCK->LFCLKSRC = 0; //disconnect XL1 AND XL2 FROM LFCLK?
+  NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
+  NRF_CLOCK->TASKS_LFCLKSTART    = 1;
+  while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0) {}
+
+  NRF_GPIO->DIRSET = (1 << pin_mode1) | (1 << pin_mode0); //set mode pins as output
+  NRF_GPIO->OUTCLR = (1 << pin_mode1) | (1 << pin_mode0); //set to full step mode
+
+  NRF_GPIO->DIRSET = (1 << pin_step) | (1 << pin_direction); //set step/dir pins as output
+  
+  
+  //NRF_TIMER1->MODE = (TIMER_MODE_MODE_Timer << TIMER_MODE_MODE_Pos) & TIMER_MODE_MODE_Msk;
+  //NRF_TIMER1->BITMODE = (TIMER_BITMODE_BITMODE_16Bit << TIMER_BITMODE_BITMODE_Pos) & TIMER_BITMODE_BITMODE_Msk;
+  //NRF_TIMER1->PRESCALER = (7 << TIMER_PRESCALER_PRESCALER_Pos) & TIMER_PRESCALER_PRESCALER_Msk;
+  //NRF_TIMER1->SHORTS = ((TIMER_SHORTS_COMPARE0_CLEAR_Enabled << TIMER_SHORTS_COMPARE0_CLEAR_Pos) & TIMER_SHORTS_COMPARE0_CLEAR_Msk);
+  //NRF_TIMER1->CC[0] = (1 << 15); //50% duty cycle to test
+
+  //enable PPI channel 0 for compare task setting pin high
+  //NRF_PPI->CHEN = (PPI_CHEN_CH0_Enabled << PPI_CHEN_CH0_Pos) & PPI_CHEN_CH0_Msk;
+  //NRF_PPI->CH[0].EEP = (uint32_t)&NRF_TIMER1->EVENTS_COMPARE[0];
+  //NRF_PPI->CH[0].TEP = (uint32_t)&NRF_GPIOTE->TASKS_OUT[0];
+  //enable PPI channel 1 for compare overflow setting pin low
+  //NRF_PPI->CHEN = (PPI_CHEN_CH1_Enabled << PPI_CHEN_CH1_Pos) & PPI_CHEN_CH1_Msk;
+  //NRF_PPI->CH[0].EEP = (uint32_t)&NRF_TIMER1->EVENTS_;
+  //NRF_PPI->CH[0].TEP = (uint32_t)&NRF_GPIOTE->TASKS_OUT[1];
+
+  //NRF_TIMER1->TASKS_START = 1;  //start timer
+
+  //Use PWM module
+  NRF_GPIO->DIRSET = (1<<pin_ref); //set ref pin as output
+  NRF_GPIO->OUTCLR = (1<<pin_ref); //set ref pin low
+  NRF_PWM0->PSEL.OUT[0] = (pin_ref << PWM_PSEL_OUT_PIN_Pos) | (PWM_PSEL_OUT_CONNECT_Connected << PWM_PSEL_OUT_CONNECT_Pos); //set aref pin to pwm out[0]
+  NRF_PWM0->ENABLE = (PWM_ENABLE_ENABLE_Enabled << PWM_ENABLE_ENABLE_Pos);
+  NRF_PWM0->MODE = (PWM_MODE_UPDOWN_Up << PWM_MODE_UPDOWN_Pos);
+  NRF_PWM0->PRESCALER = (PWM_PRESCALER_PRESCALER_DIV_1 << PWM_PRESCALER_PRESCALER_Pos); //16MHz tick
+  NRF_PWM0->COUNTERTOP = (1600 << PWM_COUNTERTOP_COUNTERTOP_Pos); //1 kHz pwm freq.
+  NRF_PWM0->LOOP = (PWM_LOOP_CNT_Disabled << PWM_LOOP_CNT_Pos);
+  NRF_PWM0->DECODER = (PWM_DECODER_LOAD_Common << PWM_DECODER_LOAD_Pos) | (PWM_DECODER_MODE_RefreshCount << PWM_DECODER_MODE_Pos);
+  pwms[0] = 1500; //50% duty cycle to test
+  delay(1);
+  NRF_PWM0->SEQ[0].PTR = ((uint32_t)(pwms) << PWM_SEQ_PTR_PTR_Pos);
+  NRF_PWM0->SEQ[0].CNT = (1 << PWM_SEQ_CNT_CNT_Pos);
+  NRF_PWM0->SEQ[0].REFRESH = 0;
+  NRF_PWM0->SEQ[0].ENDDELAY = 0;
+  NRF_PWM0->TASKS_SEQSTART[0] = 1;
+  
+  delay(1); //give aref filter time to settle.
+
+  NRF_GPIO->OUTSET = (1<<pin_nrst); //set nrst/nslp high to enable drv8825
+  NRF_GPIO->OUTSET = (1<<pin_direction); //set nrst/nslp high to enable drv8825
+
+  while (true) {
+    //Serial.println("hi there");
+    NRF_GPIO->OUTSET = (1<<pin_step);
+    delay(10);
+    NRF_GPIO->OUTCLR = (1<<pin_step);
+    delay(1);
+  }
+}
+
+
+
+
+void loop() {}