fixed adc read ???

git-svn-id: https://svn.spreadspace.org/mur.sat@448 7de4ea59-55d0-425e-a1af-a3118ea81d4c

2 files changed, 16 insertions, 15 deletions

diff --git a/software/hhd70dongle/util.c b/software/hhd70dongle/util.c
index b0e6e89..2c358fa 100644
--- a/software/hhd70dongle/util.c
+++ b/software/hhd70dongle/util.c
@@ -70,18 +70,20 @@ void reset(void)
   #endif 
 }
 
-int16_t adc_read(uint8_t mux)
+uint8_t adc_read(uint8_t mux)
 {
-    uint8_t low;
-    char aref = 0b01000000;
-    ADCSRA = (1<<ADEN) | ADC_PRESCALER;             // enable ADC
-    ADCSRB = (1<<ADHSM) | (mux & 0x20);             // high speed mode
-    ADMUX = aref | (mux & 0x1F);                    // configure mux input
-    ADCSRA = (1<<ADEN) | ADC_PRESCALER | (1<<ADSC); // start the conversion
+    ADCSRB = (mux & 0x20);                          // select input 
+    ADMUX = 0b11100000 | (mux & 0x1F);              // select input cont'd
+                                                    // select internal 2.56V reference,
+                                                    // result is left justified
+    ADCSRA = (1<<ADEN) | 0b00000111;                // enable ADC, Prescaler 1:128
+
+    ADCSRA |= (1<<ADSC);                            // start the conversion
     while (ADCSRA & (1<<ADSC)) ;                    // wait for result
-    low = ADCL;                                     // must read LSB first
-    ADCSRA &= ~(1<<ADEN);             // disable ADC
-    return (ADCH << 8) | low;                       // must read MSB only once!
+
+    ADCSRA &= ~(1<<ADEN);                           // disable ADC -> save power
+
+    return ADCH;
 }
 
 void debug_sprint_int16hex(uint8_t *buffer, int16_t num)
@@ -93,4 +95,4 @@ void debug_sprint_int16hex(uint8_t *buffer, int16_t num)
         buffer[c] = n + ((n < 10) ? '0' : 'A' - 10);
     }
     buffer[4]=0;
-}
\ No newline at end of file
+}
diff --git a/software/hhd70dongle/util.h b/software/hhd70dongle/util.h
index 1c4cb21..20068fd 100644
--- a/software/hhd70dongle/util.h
+++ b/software/hhd70dongle/util.h
@@ -32,13 +32,12 @@
 
 #ifndef MURSAT_util_h_INCLUDED
 #define MURSAT_util_h_INCLUDED
-#define ADC_PRESCALER 0
-#define ADCMUX_INTERNALTEMP 0b100111
-#define ADCMUX_ADC12 0b100100
 
+#define ADCMUX_INTERNALTEMP 0b00100111
+#define ADCMUX_ADC12 0b00100100
 
 void reset(void);
-int16_t adc_read(uint8_t mux);
+uint8_t adc_read(uint8_t mux);
 void debug_sprint_int16hex(uint8_t *buffer, int16_t num);
 
 #endif