From: Philipp Klaus <klaus@physik.uni-frankfurt.de>
Date: Thu, 6 Aug 2015 09:30:23 +0000 (+0200)
Subject: statemachine and ADC (internal and SPI) added
X-Git-Url: https://jspc29.x-matter.uni-frankfurt.de/git/?a=commitdiff_plain;h=ee77d4b4b5ba7d4223f454487e44ff1fd6c1181a;p=avr.git

statemachine and ADC (internal and SPI) added
---

diff --git a/pt100/ads_adc.h b/pt100/ads_adc.h
new file mode 100644
index 0000000..9e53877
--- /dev/null
+++ b/pt100/ads_adc.h
@@ -0,0 +1,23 @@
+
+
+//// ADC ADS1018 Definitions
+// SS "Single-shot conversion start"
+#define ADS_SConv (1 << 15)
+// MUX "Input multiplexer"
+#define ADS_MUX_AIN1_GND (0b101 << 12)
+#define ADS_MUX_AIN0_AIN3 (0b001 << 12)
+// PGA "programmable gain amplifier"
+#define ADS_GAIN_4V (0b001 << 9)
+#define ADS_GAIN_2V (0b010 << 9)
+#define ADS_GAIN_1V (0b011 << 9)
+#define ADS_GAIN_025V (0b111 << 9)
+// MODE "device operating mode"
+#define ADS_MODE_S (1 << 8)
+// DR "Data rate"
+#define ADS_1600SPS (0b100 << 5)
+#define ADS_128SPS (0b000 << 5)
+// PULL_UP_EN "Pull-up enable"
+#define ADS_PULLUP_DRDY (1 << 3)
+// NOP "No operation"
+#define ADS_WRITE_CONFIG (0b01 << 1)
+
diff --git a/pt100/main.c b/pt100/main.c
index e54de4d..c2b4f07 100644
--- a/pt100/main.c
+++ b/pt100/main.c
@@ -67,12 +67,12 @@ void init(void) {
 //CPU Regs
   
 //Init ADC SPI
-  SPCR  = (0 << SPIE) | (1 << SPE ) | (0 << DORD) | (1 << MSTR) | (0 << CPOL) | (0 << CPHA) | (0 << SPR0);
-  SPSR  = (1 << SPI2X);  //fcpu/8
+  SPCR  = (0 << SPIE) | (1 << SPE ) | (0 << DORD) | (1 << MSTR) | (0 << CPOL) | (1 << CPHA) | (0 << SPR0);
+  SPSR  = (1 << SPI2X);  //fcpu/2
   DDRB |= (1 << PB7) | (1 << PB5) | (1 << PB4); //ADC has three control lines
  
 //Init ADC for presence measurement
-  ADMUX  = (3 << REFS0) | (1 << ADLAR) | (3 << MUX0);
+  ADMUX  = (3 << REFS0) | (1 << ADLAR) | (3 << MUX0); // internal2.56V  ADC3
   ADCSRA = (1 << ADEN) | (0 << ADIE) | (5 << ADPS0);  //fcpu/32
   DIDR0  = 0x08;  //PA3 is analog only
 
diff --git a/pt100/tempmeas.c b/pt100/tempmeas.c
index 8a1b0c9..93d93d3 100644
--- a/pt100/tempmeas.c
+++ b/pt100/tempmeas.c
@@ -1,8 +1,10 @@
 #include "main.h"
+#include "ads_adc.h"
 
+#define CONNECTED_SENSORS 8
 
-uint8_t connected_sensors = 0x1a;
 uint8_t measurement_step;
+uint8_t current_channel = 0;
 
 
 //factors: gain_current has 2^29, ADC has 2^7 steps per mV
@@ -62,14 +64,76 @@ int32_t res_to_temp(int16_t res) {
 //34 read ADC temperature as 9th channel
 //35 send ADC temperature
  
-
 void do_measurement_step(void) {
-  if(measurement_step == 0) {
-   LED1_ON();
-   }
-  else if(measurement_step == 36) {
-    measurement_active = 0;
-    LED1_OFF();
+  if(measurement_step < (CONNECTED_SENSORS*4) && measurement_step & 0x3 == 0x0) {
+    LED1_ON();
+    select_channel();
+    }
+  else if(measurement_step < (CONNECTED_SENSORS*4) && measurement_step & 0x3 == 0x1) {
+    ADCSRA |= (1<<ADSC); //start ADC conversion
+    uint16_t conf_register = (ADS_MODE_S | ADS_GAIN_025V |
+        ADS_SConv | ADS_WRITE_CONFIG | ADS_PULLUP_DRDY | ADS_1600SPS);
+    conf_register |= ADS_MUX_AIN0_AIN3;
+    SPI_transceive_16bit(conf_register);
+    }
+  else if(measurement_step < (CONNECTED_SENSORS*4) && measurement_step & 0x3 == 0x2) {
+    set_inhibit_signals(1);
+    uint16_t x;
+    // read on / off
+    x = ADCL;
+    x += (ADCH<<8);
+    // should be
+    // (5 - 2.2E3 * 410E-6) / 2 = 2.049 V if on
+    // (5 - 2.2E3 *  10E-6) / 2 = 2.489 V if off
+    // -> compare to 2.27 V or (2.27/2.56)*2^16 = 58112
+    if (x < 58112) {
+      // read value
+      x = SPI_transceive_16bit(0x0000);
+      x = res_to_temp(adc_to_res(x));
+      void send_answer_hex(0, 0, x);
+      }
+    else {
+      void send_answer_hex(0, 0, (1<< (5*4)));
+      }
+  else if(measurement_step < (CONNECTED_SENSORS*4) && measurement_step & 0x3 == 0x3) {
+    selected_channel += 1;
+    }
+  measurement_step += 1;
+  if(measurement_step == 36)
     measurement_step = 0;
+    selected_channel = 0
+    LED1_OFF();
+    measurement_active = 0;
+  }
+
+
+void set_inhibit_signals(int on_off) {
+  PORTC = (PORTC & 0x3F) | (on_off << 6);
+  }
+
+void select_channel() {
+  if (current_channel == 8) {
+    // temperature measurement
+    set_inhibit_signals(0);
     }
+  else {
+    // update the select outputs
+    PORTA = (PORTA & 0x8F) | (current_channel << 4);
+    // clear inhibit signals
+    set_inhibit_signals(0);
+    }
+  }
+
+uint16_t SPI_transceive_16bit(uint16_t data){
+  char high, low;
+  high = SPI_transceive(data>>8);
+  low = SPI_transceive(data&0xFF);
+  return (high << 8) | low;
   }
+
+char SPI_transceive(unsigned char cData){
+  SPDR = cData;
+  while (!(SPSR & (1<<SPIF)))
+    ;
+  return SPDR;
+  }
\ No newline at end of file