Merge pull request #240 from boramonideep/adc_diff_gain

Variable gain ADC feature
Infineon · May 5, 2023 · f58509d · f58509d
2 parents a514687 + 448e285
commit f58509d
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diff --git a/cores/wiring_analog.c b/cores/wiring_analog.c
@@ -216,6 +216,70 @@ if( channel < NUM_ANALOG_INPUTS )
 return value;
 }
 
+/* analogRead_variableGain takes parameter of ADC channel number and gain value
+      return 0xFFFFFFFF for invalid channel
+
+     gain value    gain factor
+         0             1
+         1             3
+         2             6
+         3             12
+    Also, refer to macros in wiring_analog.h          
+*/ 
+
+uint32_t analogRead_variableGain( uint8_t channel, uint8_t gain_value )
+{
+#if(XMC_VADC_SHS_AVAILABLE == 1U)
+uint32_t value;
+
+value = 0xFFFFFFFF;
+if( channel < NUM_ANALOG_INPUTS )
+  {
+  XMC_ADC_t *adc = &mapping_adc[ channel ];
+
+#if(XMC_VADC_GROUP_AVAILABLE == 1U)
+  // ADC grouping
+  if( !(adc->enabled) )
+    {
+    XMC_VADC_CHANNEL_CONFIG_t  vadc_gobal_channel_config;
+    memset( &vadc_gobal_channel_config, 0, sizeof( XMC_VADC_CHANNEL_CONFIG_t ) );
+    vadc_gobal_channel_config.input_class       = XMC_VADC_CHANNEL_CONV_GROUP_CLASS1;
+    vadc_gobal_channel_config.result_reg_number = adc->result_reg_num;
+    vadc_gobal_channel_config.alias_channel     = XMC_VADC_CHANNEL_ALIAS_DISABLED;
+
+    XMC_VADC_RESULT_CONFIG_t vadc_gobal_result_config = { .g_rcr = 0 };
+    /* Configure a channel belonging to the aforesaid conversion kernel */
+    XMC_VADC_GROUP_ChannelInit( adc->group, adc->channel_num, &vadc_gobal_channel_config );
+    /* Configure a result resource belonging to the aforesaid conversion kernel */
+    XMC_VADC_GROUP_ResultInit( adc->group, adc->result_reg_num, &vadc_gobal_result_config );
+    /* Add channel into the Background Request Source Channel Select Register */
+    XMC_VADC_GLOBAL_BackgroundAddChannelToSequence( VADC, (uint32_t)adc->group_num,
+                                                          (uint32_t)adc->channel_num );                                                         
+    /* Set the gain factor of the Sample and hold module*/
+    XMC_VADC_GLOBAL_SHS_SetGainFactor( SHS0, gain_value, (uint32_t)adc->group_num, (uint32_t)adc->channel_num );                                                          
+    }
+  /* Start conversion manually using load event trigger*/
+  XMC_VADC_GLOBAL_BackgroundTriggerConversion( VADC );
+  value = XMC_VADC_GROUP_GetResult( adc->group, adc->result_reg_num );
+#else
+  // XMC1100 no ADC grouping
+  if( !(adc->enabled) )
+    /* Add a channel to the background source. */
+    VADC->BRSSEL[ ADC_CONVERSION_GROUP ] = (uint32_t)( 1U << adc->channel_num );
+  /* Set the gain factor of the Sample and hold module */
+  XMC_VADC_GLOBAL_SHS_SetGainFactor( SHS0, gain_value, XMC_VADC_GROUP_INDEX_0, (uint32_t)adc->channel_num );
+  // Generates conversion request
+  XMC_VADC_GLOBAL_BackgroundTriggerConversion( VADC );
+
+  // Wait until conversion is ready
+  while( ( ( value = XMC_VADC_GLOBAL_GetDetailedResult( VADC ) ) & VADC_GLOBRES_VF_Msk) == 0u );
+#endif
+  value = ( ( value & VADC_GLOBRES_RESULT_Msk) >> ( ADC_MAX_READ_RESOLUTION - _readResolution ) );
+return value;
+  }
+#endif
+}
+
 
 /* Helper function for analogWrite and setAnalogWriteFrequency to scan
    mapping tables to determine for a given pin which PWM4, PWM8 or DAC

diff --git a/cores/wiring_analog.h b/cores/wiring_analog.h
@@ -26,6 +26,15 @@
 extern "C" {
 #endif
 
+/*********************************************************************************************************************
+ * MACROS
+ ********************************************************************************************************************/
+// ADC gain macros
+#define ADC_VAR_GAIN_FACTOR_1             0
+#define ADC_VAR_GAIN_FACTOR_3             1
+#define ADC_VAR_GAIN_FACTOR_6             2
+#define ADC_VAR_GAIN_FACTOR_12            3
+
 //****************************************************************************
 // @External Prototypes
 //****************************************************************************
@@ -85,6 +94,22 @@ extern "C" {
      */
     extern uint32_t analogRead( uint8_t channel ) ;
 
+    /*
+     * \brief Reads the value from the specified analogue channel and add variable gain at input.
+     *
+     * \param channel
+     * \param gain_factor
+     * 
+     * gain value   gain factor
+     *    0            1
+     *    1            3
+     *    2            6
+     *    3            12
+     *
+     * \return Read value from selected channel, or 0xFFFFFFFF for error.
+     */
+    extern uint32_t analogRead_variableGain( uint8_t channel, uint8_t gain_value ) ;
+
     /*
      * \brief Set the resolution of analogRead return values in number of bits.
      * \note Default is 10 bits (range from 0 to 1023).

diff --git a/keywords.txt b/keywords.txt
@@ -16,6 +16,7 @@ getAnalogReadBits	KEYWORD2
 getAnalogWriteBits	KEYWORD2
 getAnalogReadMaximum	KEYWORD2
 getAnalogWriteMaximum	KEYWORD2
+analogRead_variableGain KEYWORD2
 
 #######################################
 # Instances (KEYWORD2)