offset-compensation test (not yet working)

firmware/slavechip/main.c

@@ -26,6 +26,8 @@ void baz() {
  * - multiplexer:
  *		C3: inhibit
  *		C0-C2: muxer select
+ *	- offset measurement
+ *	    D0-D3 offset compensation
  *
  *
  * amp 0 is on muxer channel 2
@@ -47,6 +49,7 @@ void hardinit() {
   spi_init();
 
   muxer_init();
+  offset_measure_init();
   
   i2c_init();
 
@@ -96,6 +99,19 @@ int __attribute__((noreturn)) main(void) {
 		dbgLog("temp: %6li (%li µV, %li mK)\n",temp,nV/1000, mK);
 	}
 
+	SOFTTIMER(3,4000){
+		static uint8_t toggle;
+		if(toggle){
+			offset_measure_start(0);
+			toggle=0;
+			dbgLog("measuring offset\n");
+		} else {
+			offset_measure_stop();
+			toggle=1;
+			dbgLog("stopping offset-measuring\n");
+		}
+	}
+
   }
 }
 

firmware/slavechip/muxer.c

@@ -14,3 +14,19 @@ void muxer_set(uint8_t channel){
 	//TODO: delays, check everything, mask in register
 }
 
+
+void offset_measure_init(){
+	DDRD |= 0x0f; // first 4 pins as output
+	PORTD = 0x00; // turn everything off
+}
+
+void offset_measure_start(uint8_t channel){
+	if(channel >3){
+		return;
+	}
+	PORTD = (1<<channel);
+}
+
+void offset_measure_stop(){
+	PORTD = 0;
+}

firmware/slavechip/muxer.h

@@ -4,3 +4,7 @@
 
 void muxer_init();
 void muxer_set(uint8_t channel);
+
+void offset_measure_init();
+void offset_measure_start(uint8_t channel);
+void offset_measure_stop();