better timing (throwing away values) in measurement, less prints, less baudrate, static offsets. This version is working pretty nicely.

firmware/masterchip/spi_config.h

@@ -1,5 +1,5 @@
 
-#define SPI_BAUDRATE 40000
+#define SPI_BAUDRATE 20000
 #define SPI_MASTER
 #define SPI_SS_PORT D
 #define SPI_SS_PIN 7

firmware/slavechip/filter.c

@@ -14,7 +14,6 @@ float avg_noise[CHANNELCOUNT];
 
 
 void process_thermocouple_value(int16_t raw_data, uint8_t channel){
-    printf("procthermval, val %i, chan %i\n",raw_data,channel);
     // This function does everything that needs to be done to raw adc values
     float a = raw_data;
     a -= sensordata[channel].offset; 
@@ -26,7 +25,7 @@ void process_thermocouple_value(int16_t raw_data, uint8_t channel){
     
     uint16_t result = filter_float_to_fixpoint(a);
     sensordata[channel].temperature = result;
-    printf("temperature: %i.%2i\n",result/100,result%100);
+    printf("temperature: %i.%2i (val %i)\n",result/100,result%100,raw_data);
 }
 
 void process_offset_value(int16_t raw_data, uint8_t channel){

firmware/slavechip/main.c

@@ -47,7 +47,9 @@ void softinit() {
     stdout = &mystdout;
     printf("======= starting logging\n");
 	mcpadc_init(ADC_GAIN_2|ADC_CONV_CONT|ADC_BITS_16);
-    offset_init();
+//    offset_init();
+    sensordata[0].offset = -400;
+    sensordata[1].offset = +478;
 }
 
 
@@ -60,25 +62,22 @@ int __attribute__((noreturn)) main(void) {
 
 	int16_t data;
 	for(;;){
-        printf("====== loop iteration\n");
-        
-
 
 		// measure temps 5*2 times
-		for(uint8_t i=0; i<1; i++) {
-            printf("====== now measuring temps\n");
+		for(uint8_t i=0; i<5; i++) {
 			for(uint8_t active_sensor=0; active_sensor<2; active_sensor++) { // only measuring two probes atm
-                printf("=== active sensor: %i\n",active_sensor);
+              //  printf("=== active sensor: %i\n",active_sensor);
 				muxer_set(active_sensor);
+                for(uint8_t j=0; j<4; ++j){
+                    while(!mcpadc_has_new_data()) _delay_ms(10);
+                    mcpadc_get_data(); // first data after switch to trash
+                }
 				while(!mcpadc_has_new_data()) _delay_ms(10);
-				mcpadc_get_data(); // first data after switch to trash
-				while(!mcpadc_has_new_data()) _delay_ms(10);
-				_delay_ms(1000);
 				data = mcpadc_get_data();
                 process_thermocouple_value(data,active_sensor);
 			}
 		}
-
+/*
 		// measure 2 offsets
 		for(uint8_t active_sensor=0; active_sensor<2; active_sensor++)
             if(offset_measure[active_sensor]) {
@@ -95,15 +94,15 @@ int __attribute__((noreturn)) main(void) {
                     offset_count[active_sensor]++;
                 }
             }
-        
+*/        
         // measure ambient
         printf("====== now measuring ambient\n");
         muxer_set(4);
-        _delay_ms(300);
-        while(!mcpadc_has_new_data()) _delay_ms(10);
-        mcpadc_get_data(); // first data after switch to trash
         while(!mcpadc_has_new_data()) _delay_ms(10);
         mcpadc_get_data(); // first data after switch to trash
+      //  while(!mcpadc_has_new_data()) _delay_ms(10);
+      //  mcpadc_get_data(); // first data after switch to trash
+        _delay_ms(100);
         while(!mcpadc_has_new_data()) _delay_ms(10);
         data = mcpadc_get_data();
         process_ambient_value(data);