STM32F411: implement analog-stm32.c

It's not that easy like LPC. We need later an DMA to control all ADCs, because there is only one register to read the ADC.

analog-stm32.c

@@ -0,0 +1,96 @@
+
+/** \file
+  \brief Analog subsystem, ARM specific part.
+
+*/
+
+#if defined TEACUP_C_INCLUDE && defined __ARM_STM32F411__
+
+#include "cmsis-stm32f4xx.h"
+#include "arduino.h"
+#include "temp.h"
+
+
+/** Inititalise the analog subsystem.
+
+  Initialise the ADC and start hardware scan loop for all used sensors.
+*/
+void analog_init() {
+
+  if (NUM_TEMP_SENSORS) {                       // At least one channel in use.
+
+    PIOC_2_PORT->MODER |= (GPIO_MODER_MODER0 << ((PIOC_2_PIN) << 1));   // analog mode
+    PIOC_2_PORT->PUPDR &= ~(3 << ((PIOC_2_PIN) << 1));                  // no pullup
+    PIOC_2_PORT->OSPEEDR |= (3 << ((PIOC_2_PIN) << 1));                 // high speed
+
+    RCC->APB2ENR |= RCC_APB2ENR_ADC1EN; //Enable clock
+
+    /* Set ADC parameters */
+    /* Set the ADC clock prescaler */
+    /*  Datasheet says max. ADC-clock is 36MHz
+        We don't need that much. 12MHz is slowest possible.
+    */
+    ADC->CCR |= (ADC_CCR_ADCPRE);
+    
+    /* Set ADC scan mode */
+    // scan mode disabled
+    // reset resolution
+    // discontinous mode disabled
+    ADC1->CR1 &= ~( ADC_CR1_SCAN | 
+                    ADC_CR1_RES |
+                    ADC_CR1_DISCEN);
+      
+    /* Set ADC resolution */
+    // resoltion 10bit
+    ADC1->CR1 |=  ADC_CR1_RES_0;
+    
+    /* Set ADC data alignment */
+    // reset = right align
+    // reset external trigger
+    //
+    // disable continous conversion mode
+    // disable ADC DMA continuous request
+    // disable ADC end of conversion selection
+    ADC1->CR2 &= ~( ADC_CR2_ALIGN |
+                    ADC_CR2_EXTSEL |
+                    ADC_CR2_EXTEN |
+                    ADC_CR2_CONT |
+                    ADC_CR2_DDS |
+                    ADC_CR2_EOCS);
+    
+    /* Set ADC number of conversion */
+    // 1 conversion
+    ADC1->SQR1 &= ~(ADC_SQR1_L);
+
+  }
+}
+
+/** Read analog value.
+
+  \param channel Channel to be read.
+
+  \return Analog reading, 10-bit right aligned.
+
+  STM32F4 goes a different way. The ADC don't have a register for 
+  each channel. We need a DMA soon to convert and hold all datas.
+*/
+//#include "delay.h"
+uint16_t analog_read(uint8_t index) {
+  // 11.8.2 Managing a sequence of conversions without using the DMA
+  // page 220
+
+  ADC1->SMPR1 &= ~(ADC_SMPR1_SMP12);  // PIOC_2_ADC 12
+                                      // 3 CYCLES
+
+  ADC1->SQR3 &= ~(ADC_SQR3_SQ1);      // rank 1
+  ADC1->SQR3 |= PIOC_2_ADC;           // << (5 * (rank - 1))
+
+  ADC1->CR2 |=  ADC_CR2_ADON          // A/D Converter ON / OFF
+              | ADC_CR2_SWSTART;      // Start Conversion of regular channels
+
+  while (!(ADC1->SR & ADC_SR_EOC) == ADC_SR_EOC);
+
+  return ADC1->DR;
+}
+
+#endif /* defined TEACUP_C_INCLUDE && defined __ARM_STM32F411__ */

analog.c

@@ -36,6 +36,7 @@ static uint8_t adc_channel[NUM_TEMP_SENSORS] = {
 #define TEACUP_C_INCLUDE
 #include "analog-avr.c"
 #include "analog-lpc.c"
+#include "analog-stm32.c"
 #undef TEACUP_C_INCLUDE
 
 // No common code so far.

arduino_stm32f411.h

@@ -11,7 +11,7 @@
   functions, spread over various files, slow execution (pin toggling about
   15 times slower than what we have here).
 
-  FASTIO by setting the BSRR (bit set/reset register), 
+  FASTIO by setting the BSRR (bit set/reset register),
   - Bit0-15 to set
   - Bit16-31 to reset.
 
@@ -24,10 +24,10 @@
 
 /** Pins for UART, the serial port.
 */
-#define RXD_PORT        PIOA_3_PORT
-#define RXD_PIN         PIOA_3_PIN
-#define TXD_PORT        PIOA_2_PORT
-#define TXD_PIN         PIOA_2_PIN
+#define RXD_PORT        PA_3_PORT
+#define RXD_PIN         PA_3_PIN
+#define TXD_PORT        PA_2_PORT
+#define TXD_PIN         PA_2_PIN
 
 /**
   We define only pins available on the Nucleo F411RE here.
@@ -36,27 +36,35 @@
 
 #define PA_0_PIN      0
 #define PA_0_PORT     GPIOA
+#define PA_0_ADC      0
 
 #define PA_1_PIN      1
 #define PA_1_PORT     GPIOA
+#define PA_1_ADC      1
 
 #define PA_2_PIN      2
 #define PA_2_PORT     GPIOA
+#define PA_2_ADC      2
 
 #define PA_3_PIN      3
 #define PA_3_PORT     GPIOA
+#define PA_3_ADC      3
 
 #define PA_4_PIN      4
 #define PA_4_PORT     GPIOA
+#define PA_4_ADC      4
 
 #define PA_5_PIN      5
 #define PA_5_PORT     GPIOA
+#define PA_5_ADC      5
 
 #define PA_6_PIN      6
 #define PA_6_PORT     GPIOA
+#define PA_6_ADC      6
 
 #define PA_7_PIN      7
 #define PA_7_PORT     GPIOA
+#define PA_7_ADC      7
 
 #define PA_8_PIN      8
 #define PA_8_PORT     GPIOA
@@ -84,9 +92,11 @@
 
 #define PB_0_PIN      0
 #define PB_0_PORT     GPIOB
+#define PB_0_ADC      8
 
 #define PB_1_PIN      1
 #define PB_1_PORT     GPIOB
+#define PB_1_ADC      9
 
 #define PB_2_PIN      2
 #define PB_2_PORT     GPIOB
@@ -129,21 +139,27 @@
 
 #define PC_0_PIN      0
 #define PC_0_PORT     GPIOC
+#define PC_0_ADC      10
 
 #define PC_1_PIN      1
 #define PC_1_PORT     GPIOC
+#define PC_1_ADC      11
 
 #define PC_2_PIN      2
 #define PC_2_PORT     GPIOC
+#define PC_2_ADC      12
 
 #define PC_3_PIN      3
 #define PC_3_PORT     GPIOC
+#define PC_3_ADC      13
 
 #define PC_4_PIN      4
 #define PC_4_PORT     GPIOC
+#define PC_4_ADC      14
 
 #define PC_5_PIN      5
 #define PC_5_PORT     GPIOC
+#define PC_5_ADC      15
 
 #define PC_6_PIN      6
 #define PC_6_PORT     GPIOC