CosmicOscilloscope

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+#undef HID_ENABLED
+
+// Arduino Due ADC->DMA->USB 1MSPS
+// by stimmer
+// from http://forum.arduino.cc/index.php?topic=137635.msg1136315#msg1136315
+// Input: Analog in A0
+// Output: Raw stream of uint16_t in range 0-4095 on Native USB Serial/ACM
+
+// on linux, to stop the OS cooking your data: 
+// stty -F /dev/ttyACM0 raw -iexten -echo -echoe -echok -echoctl -echoke -onlcr
+
+volatile int bufn,obufn;
+uint16_t buf[4][256];   // 4 buffers of 256 readings
+
+//HV PSU init
+const int SS_pin = 42; //tbc
+const int SCK_pin = 44;
+const int MISO_pin = 22;
+const int MOSI_pin = 43;
+byte sendValue;   // Value we are going to send
+
+
+void ADC_Handler(){     // move DMA pointers to next buffer
+  int f=ADC->ADC_ISR;
+  if (f&(1<<27)){
+   bufn=(bufn+1)&3;
+   ADC->ADC_RNPR=(uint32_t)buf[bufn];
+   ADC->ADC_RNCR=256;
+  } 
+}
+
+void setup(){
+//HV Setup
+digitalWrite(SS, HIGH);  // Start with SS high
+pinMode(SS_pin, OUTPUT);
+pinMode(SCK_pin, OUTPUT);
+pinMode(MISO_pin, INPUT); //this is the avalanche pin, not implemented yet
+pinMode(MOSI_pin, OUTPUT);
+
+sendValue = 0xFF; //Set the HV here onetime
+sendValue = bitBang(sendValue); // Transmit data
+
+
+//set up the thresholds
+pinMode(35, OUTPUT); //setup for the MAX5387 - later set to 0. signal PA0
+pinMode(36, OUTPUT);//setup for the MAX5387 - later set to 0. signal PA1
+pinMode(37, OUTPUT);//setup for the MAX5387 - later set to 0. signal PA2
+digitalWrite(35, LOW);//configure the address of the MAX5387 pot
+digitalWrite(36, LOW);//configure the address of the MAX5387 pot
+digitalWrite(37, LOW);//configure the address of the MAX5387 pot
+pinMode(5, INPUT); //set the interrupt pin for trigger as high impedance, probably not required
+ 
+Wire.begin();
+Wire.beginTransmission(byte(0x28)); // transmit to device #112
+Wire.write(byte(B00010011)); //set both registers
+//Wire.write(byte(B00010001)); //set both register A only
+//Wire.write(byte(B00010010)); //set both register B only
+Wire.write(byte(0x50));// sets registers to this value (1 step = 13mV)
+Wire.endTransmission();      // stop transmitting
+
+
+  //ADC setup
+  
+  
+  SerialUSB.begin(0);
+  while(!SerialUSB);
+
+  pmc_enable_periph_clk(ID_ADC);
+  adc_init(ADC, SystemCoreClock, ADC_FREQ_MAX, ADC_STARTUP_FAST);
+  ADC->ADC_MR |=0x80; // free running
+
+  ADC->ADC_CHER=0x80; 
+
+  NVIC_EnableIRQ(ADC_IRQn);
+  ADC->ADC_IDR=~(1<<27);
+  ADC->ADC_IER=1<<27;
+  ADC->ADC_RPR=(uint32_t)buf[0];   // DMA buffer
+  ADC->ADC_RCR=256;
+  ADC->ADC_RNPR=(uint32_t)buf[1]; // next DMA buffer
+  ADC->ADC_RNCR=256;
+  bufn=obufn=1;
+  ADC->ADC_PTCR=1;
+  ADC->ADC_CR=2;
+}
+
+void loop(){
+  while(obufn==bufn); // wait for buffer to be full
+  SerialUSB.write((uint8_t *)buf[obufn],512); // send it - 512 bytes = 256 uint16_t
+  SerialUSB.write((uint8_t *)buf[obufn],512); // send it - 512 bytes = 256 uint16_t
+    obufn=(obufn+1)&3;    
+}
+
+byte bitBang(byte _send)  // This function is what bitbangs the data
+{
+
+  //reception isn't implemented in this version. 
+  byte _receive = 0;
+   digitalWrite(SS_pin, LOW);        // SS low 
+  for(int i=0; i<8; i++)  // There are 8 bits in a byte
+  {
+    digitalWrite(MOSI_pin, bitRead(_send, 7-i));    // Set MOSI
+    //delay(1);
+    digitalWrite(SCK_pin, HIGH);                  // SCK high
+    //bitWrite(_receive, i, digitalRead(MISO_pin)); // Capture MISO
+    digitalWrite(SCK_pin, LOW);                   // SCK low
+  //digitalWrite(MOSI_pin, LOW);    // Set MOSI
+    
+  }
+   digitalWrite(SS_pin, HIGH);       // SS high again 
+ 
+  //return _receive;        // Return the received data
+}
+
+//timing system
+
+void TimersStart() {
+
+        uint32_t config = 0;
+
+  // Set up the power management controller for TC0 and TC2
+
+        pmc_set_writeprotect(false);    // Enable write access to power management chip
+        pmc_enable_periph_clk(ID_TC0);  // Turn on power for timer block 0 channel 0
+        pmc_enable_periph_clk(ID_TC3);  // Turn on power for timer block 1 channel 0
+        pmc_enable_periph_clk(ID_TC6);  // Turn on power for timer block 2 channel 0
+
+  // Timer block 0 channel 0 is connected only to the PPS 
+  // We set it up to load regester RA on each PPS and reset
+  // So RA will contain the number of clock ticks between two PPS, this
+  // value is the clock frequency and should be very stable +/- one tick
+
+        config = TC_CMR_TCCLKS_TIMER_CLOCK1 |         // Select fast clock MCK/2 = 42 MHz
+                 TC_CMR_ETRGEDG_RISING |              // External trigger rising edge on TIOA0
+                 TC_CMR_ABETRG |                      // Use the TIOA external input line
+                 TC_CMR_LDRA_RISING;                  // Latch counter value into RA
+
+        TC_Configure(TC0, 0, config);                 // Configure channel 0 of TC0
+        TC_Start(TC0, 0);                             // Start timer running
+
+        TC0->TC_CHANNEL[0].TC_IER =  TC_IER_LDRAS;    // Enable the load AR channel 0 interrupt each PPS
+        TC0->TC_CHANNEL[0].TC_IDR = ~TC_IER_LDRAS;    // and disable the rest of the interrupt sources
+        NVIC_EnableIRQ(TC0_IRQn);                     // Enable interrupt handler for channel 0
+
+  // Timer block 1 channel 0 is the PLL for when the GPS chip isn't providing the PPS
+  // it has the frequency loaded in reg C and is triggered from the TC0 ISR
+
+  config = TC_CMR_TCCLKS_TIMER_CLOCK1 |         // Select fast clock MCK/2 = 42 MHz
+     TC_CMR_CPCTRG;       // Compare register C with count value
+
+        TC_Configure(TC1, 0, config);                 // Configure channel 0 of TC1
+        TC_SetRC(TC1, 0, FREQ);       // One second approx initial PLL value
+  TC_Start(TC1, 0);                             // Start timer running
+
+        TC1->TC_CHANNEL[0].TC_IER =  TC_IER_CPCS; // Enable the C register compare interrupt
+        TC1->TC_CHANNEL[0].TC_IDR = ~TC_IER_CPCS; // and disable the rest
+        NVIC_EnableIRQ(TC3_IRQn);     // Enable interrupt handler for channel 0
+
+  // Timer block 2 channel 0 is connected to the RAY event
+  // It is kept in phase by the PPS comming from TC0 when the PPS arrives
+  // or from TC1 when the PLL is active (This is the so called software diode logic)
+ 
+        config = TC_CMR_TCCLKS_TIMER_CLOCK1 |         // Select fast clock MCK/2 = 42 MHz
+                 TC_CMR_ETRGEDG_RISING |              // External trigger rising edge on TIOA1
+                 TC_CMR_ABETRG |                      // Use the TIOA external input line
+                 TC_CMR_LDRA_RISING;                  // Latch counter value into RA
+  
+  TC_Configure(TC2, 0, config);                 // Configure channel 0 of TC2
+  TC_Start(TC2, 0);           // Start timer running
+ 
+  TC2->TC_CHANNEL[0].TC_IER =  TC_IER_LDRAS;    // Enable the load AR channel 0 interrupt each PPS
+  TC2->TC_CHANNEL[0].TC_IDR = ~TC_IER_LDRAS;    // and disable the rest of the interrupt sources
+  NVIC_EnableIRQ(TC6_IRQn);                     // Enable interrupt handler for channel 0
+
+  // Set up the PIO controller to route input pins for TC0 and TC2
+
+  PIO_Configure(PIOC,PIO_INPUT,
+          PIO_PB25B_TIOA0,  // D2 Input 
+          PIO_DEFAULT);
+
+  PIO_Configure(PIOC,PIO_INPUT,
+          PIO_PC25B_TIOA6,  // D5 Input
+          PIO_DEFAULT);
+}
+
+// Timer chip interrupt handlers try to get time stamps to within 4 system clock ticks
+
+static uint32_t displ = 0;  // Display values in loop
+
+static uint32_t rega0 = FREQ,   // RA reg
+    stsr0 = 0,  // Interrupt status register
+    ppcnt = 0,  // PPS count
+    delcn = 0;  // Synthetic PPS ms
+
+static uint32_t rega1, stsr1 = 0;
+
+static uint32_t stsr2 = 0;
+
+boolean pll_flag = false; 
+
+int old_ra = 0;
+int new_ra = 0;
+#define DEAD_TIME 42000 // 1ms
+
+// Handle the PPS interrupt in counter block 0 ISR
+
+void TC0_Handler() {
+
+  // In principal we could connect a diode
+  // to pass on the PPS to counter blocks 1 & 2. However for some unknown
+  // reason this pulls down the PPS voltage level to less than 1V and
+  // the trigger becomes unreliable !! 
+  // In any case the PPS is 100ms wide !! Introducing a blind spot when
+  // the diode creates the OR of the event trigger and the PPS.
+  // So this is a software diode
+
+  TC2->TC_CHANNEL[0].TC_CCR = TC_CCR_SWTRG; // Forward PPS to counter block 2
+  TC1->TC_CHANNEL[0].TC_CCR = TC_CCR_SWTRG; // Forward PPS to counter block 1
+
+  rega0 = TC0->TC_CHANNEL[0].TC_RA; // Read the RA reg (PPS period)
+  stsr0 = TC_GetStatus(TC0, 0);     // Read status and clear load bits
+
+  if (rega0 < MFRQ)     // Sanity check against noise
+    rega0 = FREQ;     // Use nominal value
+  
+        TC_SetRC(TC1, 0, rega0);    // Set the PLL count to what we just counted
+
+  SwapBufs();       // Every PPS swap the read/write buffers
+  ppcnt++;        // PPS count
+  displ = 1;        // Display stuff in the loop
+  gps_ok = true;        // Its OK because we got a PPS  
+  pll_flag = true;      // Inhibit PLL, dont take over PPS arrived
+
+  old_ra = 0;       // Dead time counters
+  new_ra = 0;
+  
+  IncDateTime();        // Next second
+
+  if (pps_led) {    
+    digitalWrite(PPS_PIN,HIGH);
+    pps_led = false;
+  } else {
+    digitalWrite(PPS_PIN,LOW);
+    pps_led = true;
+  }
+}
+
+// Handle PLL interrupts
+// When/If the PPS goes missing due to a lost lock we carry on with the last measured
+// value for the second from TC0
+
+void TC3_Handler() {
+
+  stsr2 = TC_GetStatus(TC1, 0);     // Read status and clear interrupt
+#if FLG_PIN
+  digitalWrite(FLG_PIN,HIGH);   // Flag set (for debug)
+  digitalWrite(FLG_PIN,LOW);
+#endif
+
+  if (pll_flag == false) {    // Only take over when no PPS
+
+    TC2->TC_CHANNEL[0].TC_CCR = TC_CCR_SWTRG; // Forward PPS to counter block 2
+    SwapBufs();       // Every PPS swap the read/write buffers
+    ppcnt++;        // PPS count
+    displ = 1;        // Display stuff in the loop
+    gps_ok = false;       // PPS missing
+
+    IncDateTime();        // Next second
+  }
+  pll_flag = false;       // Take over until PPS comes back
+}
+
+// We need a double buffer, one is being written by the ISR while
+// the other is read from user space within one second.