mcpadc working a little, still some unknown bug

firmware/slavechip/main.c

@@ -49,17 +49,12 @@ void hardinit() {
 }
 
 void softinit() {
-	// TODO: to prevent evil random access and stuff?
-	temperatures[0] = 0;
-	temperatures[1] = 0;
-	temperatures[2] = 0;
-	temperatures[3] = 0;
 	
 	//test values
 	foo = 0x87;
 	bar= 0xfafa;
 
-	mcpadc_init(ADC_GAIN_2|ADC_CONV_SINGLE|ADC_BITS_16);
+	mcpadc_init(ADC_GAIN_2|ADC_CONV_CONT|ADC_BITS_16);
 
 }
 
@@ -71,11 +66,11 @@ int __attribute__((noreturn)) main(void) {
   softinit();
 
   muxer_set(MUXER_CHANNEL_0);
-  temperatures[2]=33;
+  temperatures[2]=0;
 
   for(;;){
     
-    SOFTTIMER(1,100) {
+    SOFTTIMER(1,10) {
 		if(mcpadc_has_new_data()) {
 			temperatures[0] = mcpadc_get_data();
 			temperatures[2]++;

firmware/slavechip/mcp_adc.c

@@ -30,16 +30,25 @@
 
 uint8_t r[4];
 uint8_t curmode;
+uint8_t unread_data_available;
+
 
 void mcpadc_init(uint8_t mode)
 {
-	i2c_write(ADC_ADDR, 1, &mode);
+	int written = i2c_write(ADC_ADDR, 1, &mode);
+	if(written!=1){
+		for(;;); //TODO: error reporting
+	}
 	curmode = mode;
 }
 
 uint8_t mcpadc_has_new_data(void)
 {
 	/* this assumes that the first RDY bit read after the sample data indicates the old/new state of the sample we just read */
+	if(unread_data_available){
+		// we already have new data, don't overwrite that by reading more
+		return unread_data_available;
+	}
 #if ADC_ENABLE_18_BIT_MODE
 	if(curmode & ADC_BITS_MASK == ADC_BITS_18)
 	{
@@ -47,18 +56,24 @@ uint8_t mcpadc_has_new_data(void)
 		curmode = r[3];
 	}
 	else
-#endif
+#else
 	{
 		i2c_read(ADC_ADDR, 3, r);
 		curmode = r[2];
 	}
-	if(~curmode & ADC_NEW_SAMPLE) {curmode &= ADC_READ_DATA;}
-	return ~curmode & ADC_READ_DATA;
+#endif
+	if(!(curmode & ADC_NEW_SAMPLE)){ // if the /RDY bit reads 0, we just read a new sample
+		unread_data_available = 1;
+	}	
+	return unread_data_available;
 }
 
 #if ADC_ENABLE_18_BIT_MODE
 int32_t mcpadc_get_data(void)
 {
+	if(!unread_data_available){
+		return 0;
+	}
 	int32_t value = 0;
 	if(r[0] & 0x80) {value = 0xffff;}
 	value = (value << 16) | (r[0] << 8) | r[1];
@@ -66,14 +81,19 @@ int32_t mcpadc_get_data(void)
 	{
 		value = (value << 8) | r[2];
 	}
-	curmode |= (ADC_NEW_SAMPLE & ADC_READ_DATA);
+	curmode |= (ADC_NEW_SAMPLE);
+	unread_data_available = 0;
 	return value;
 }
 #else
 int16_t mcpadc_get_data(void)
 {
+	if(!unread_data_available){
+		return 0;
+	}
 	int16_t value = (r[0] << 8) | r[1];
 	curmode |= (ADC_NEW_SAMPLE & ADC_READ_DATA);
+	unread_data_available = 0;
 	return value;
 }
 #endif
@@ -82,5 +102,6 @@ void mcpadc_start_conv(void)
 {
 	r[3] = curmode | ADC_NEW_SAMPLE;
 	i2c_write(ADC_ADDR, 1, &(r[3]));
-	curmode |= (ADC_NEW_SAMPLE & ADC_READ_DATA);/* you asked for a new sample - no you won't get the old one */
+//	curmode |= (ADC_NEW_SAMPLE & ADC_READ_DATA);/* you asked for a new sample - no you won't get the old one */
+	unread_data_available = 0;
 }