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inc/DAC.c

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+/* DAC.c
+ * Jonathan Valvano
+ * November 30, 2022
+ * Derived from dac12_fixed_voltage_vref_internal_LP_MSPM0G3507_nortos_ticlang
+ *              dac12_fifo_timer_event_LP_MSPM0G3507_nortos_ticlang
+ */
+// PA15 J3.30  DACout
+
+
+#include <ti/devices/msp/msp.h>
+#include "../inc/DAC.h"
+#include "../inc/Clock.h"
+// Assumes 40 or 80 MHz MHz bus
+void DAC_Init(void){
+    // Reset DAC and VREF
+    // RSTCLR
+    //   bits 31-24 unlock key 0xB1
+    //   bit 1 is Clear reset sticky bit
+    //   bit 0 is reset ADC
+  VREF->GPRCM.RSTCTL = 0xB1000003;
+  DAC0->GPRCM.RSTCTL = 0xB1000003;
+
+    // Enable power ADC and VREF
+    // PWREN
+    //   bits 31-24 unlock key 0x26
+    //   bit 0 is Enable Power
+  VREF->GPRCM.PWREN = 0x26000001;
+  DAC0->GPRCM.PWREN = 0x26000001;
+
+  Clock_Delay(24); // time for ADC and VREF to power up
+
+  VREF->CLKSEL = 0x00000008; // bus clock
+  VREF->CLKDIV = 0; // divide by 1
+  VREF->CTL0 = 0x0001;
+  // bit 8 SHMODE = off
+  // bit 7 BUFCONFIG=0 for 2.5 (=1 for 1.4)
+  // bit 0 is enable
+  VREF->CTL2 = 0;
+  // bits 31-16 HCYCLE=0
+    // bits 15-0 SHCYCLE=0
+  while((VREF->CTL1&0x01)==0){}; // wait for VREF to be ready
+  // CTL0
+  // bit 16 DFM 0 straight binary
+  // bit 8 RES 1 12-bit
+  // bit 0 ENABLE 1 for on, 0 for disable
+  DAC0->CTL0 = 0x0100; // 12-bit, straight, disable
+  // CTL1
+  // bit 24 OPS 1 OUT0 is selected
+  // bit 9 REFSN 0 VR- is VrefN, 1 for analog ground
+  // bit 8 REFSP 1 VR+ is VrefP, 0 for analog supply
+  // bit 1 AMPHIZ 0 HiZ when disabled
+  // bit 0 AMPEN 1 enabled
+  DAC0->CTL1 = (1<<24)|(1<<9)|(1<<8)|1;
+ // DAC0->CTL1 = (1<<24)|(1<<9)|1;
+  DAC0->CTL2 = 0; // no DMA, no FIFO trigger
+  // CTL3
+  // bits 11-8 STIMCONFIG n=0 for 500 sps
+  //     for n = 0 to 5 500*2^n sps (500 to  16k)
+  //     n=6 100 ksps
+  //     n=7 200 ksps
+  //     n=8 500 ksps
+  //     n=9 1 Msps
+  // bit 0 STIMEN =0 disable sample time generator
+  DAC0->CTL3 = 0x0700; // no sample time generator
+  DAC0->CTL0 = 0x0101; // 12-bit, straight, enable
+}
+
+// output to 12-bit DAC
+void DAC_Out(uint32_t data){
+  DAC0->DATA0 = data;
+}