fixup! cpu/sam0_common: implement 16 bit mode by oversampling

RIOT-OS · Feb 15, 2023 · 0e6d45e · 0e6d45e
1 parent 6917b90
commit 0e6d45e
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Showing 2 changed files with 14 additions and 6 deletions.
diff --git a/cpu/sam0_common/include/periph_cpu_common.h b/cpu/sam0_common/include/periph_cpu_common.h
@@ -821,11 +821,17 @@ typedef enum {
     ADC_RES_10BIT = ADC_CTRLC_RESSEL_10BIT_Val, /**< ADC resolution: 10 bit */
     ADC_RES_12BIT = ADC_CTRLC_RESSEL_12BIT_Val, /**< ADC resolution: 12 bit */
 #endif
-    ADC_RES_16BIT_2SAMPL    = ( 1 << 2) | 0x1,  /**< sum of 2 12 bit samples    */
-    ADC_RES_16BIT_4SAMPL    = ( 2 << 2) | 0x1,  /**< sum of 4 12 bit samples    */
-    ADC_RES_16BIT_8SAMPL    = ( 3 << 2) | 0x1,  /**< sum of 8 12 bit samples    */
-    ADC_RES_16BIT_16SAMPL   = ( 4 << 2) | 0x1,  /**< sum of 16 12 bit samples   */
-    ADC_RES_14BIT = 0xfe,                       /**< not supported */
+    ADC_RES_16BIT_2SAMPL    = ( 0x1 << 2) | 0x1, /**< sum of 2 12 bit samples    */
+    ADC_RES_16BIT_4SAMPL    = ( 0x2 << 2) | 0x1, /**< sum of 4 12 bit samples    */
+    ADC_RES_16BIT_8SAMPL    = ( 0x3 << 2) | 0x1, /**< sum of 8 12 bit samples    */
+    ADC_RES_16BIT_16SAMPL   = ( 0x4 << 2) | 0x1, /**< sum of 16 12 bit samples   */
+    ADC_RES_16BIT_32SAMPL   = ( 0x5 << 2) | 0x1, /**< sum of 32 12 bit samples   */
+    ADC_RES_16BIT_64SAMPL   = ( 0x6 << 2) | 0x1, /**< sum of 64 12 bit samples   */
+    ADC_RES_16BIT_128SAMPL  = ( 0x7 << 2) | 0x1, /**< sum of 128 12 bit samples  */
+    ADC_RES_16BIT_256SAMPL  = ( 0x8 << 2) | 0x1, /**< sum of 256 12 bit samples  */
+    ADC_RES_16BIT_512SAMPL  = ( 0x9 << 2) | 0x1, /**< sum of 512 12 bit samples  */
+    ADC_RES_16BIT_1024SAMPL = ( 0xA << 2) | 0x1, /**< sum of 1024 12 bit samples */
+    ADC_RES_14BIT = 0xfe,                        /**< not supported */
 } adc_res_t;
 
 #define ADC_RES_16BIT   ADC_RES_16BIT_16SAMPL   /**< default to 16x oversampling */

diff --git a/cpu/sam0_common/periph/adc.c b/cpu/sam0_common/periph/adc.c
@@ -23,6 +23,7 @@
 #include "periph/gpio.h"
 #include "periph/adc.h"
 #include "periph_conf.h"
+#include "macros/utils.h"
 #include "mutex.h"
 
 #define ENABLE_DEBUG 0
@@ -339,7 +340,8 @@ int32_t adc_sample(adc_t line, adc_res_t res)
 
     /* 16 bit mode is implemented as oversampling */
     if ((res & 0x3) == 1) {
-        result <<= (4 - (res >> 2));
+        /* ADC does automatic right shifts beyond 16 samples */
+        result <<= (4 - MIN(4, res >> 2));
     }
 
     return result;