OK, below are the parts of the original appnote code which were somehow modified...
/* USER CODE BEGIN PV */
/* Private variables ---------------------------------------------------------*/
#define DITHER_TABLE_FIRST_PART ((uint32_t*) aDitherTable) // 3 bits EXTRA
#define DITHER_TABLE_SECOND_PART ((uint32_t*)(aDitherTable + 4)) //was +8
//the defines could be removed as we have two different functions to update the aDitherTable[8]
#define TIMER_PERIOD ((uint32_t)16)
uint32_t aDitherTable[8]; //was [16]
uint32_t DitherIndex = 0;
uint32_t DCycleIndex = 0;
uint32_t UpCounting = 1;
//this table gives optimal dithering pattern in contrast to the original function "UpdateDitherTable"
uint32_t ditable[8][8]={{0,0,0,0,0,0,0,0}, //0
{1,0,0,0,0,0,0,0}, //1
{1,0,0,0,1,0,0,0}, //2
{1,0,0,1,0,0,1,0}, //3
{1,0,1,0,1,0,1,0}, //4
{1,1,1,0,1,0,1,0}, //5
{1,1,1,0,1,1,1,0}, //6
{1,1,1,1,1,1,1,0}}; //7
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
void Error_Handler(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_TIM1_Init(void);
void HAL_TIM_MspPostInit(TIM_HandleTypeDef *htim);
/* USER CODE BEGIN PFP */
/* Private function prototypes -----------------------------------------------*/
HAL_StatusTypeDef TIM1_PWM_UPDATE_DMA(TIM_HandleTypeDef *htim, uint32_t *pData,uint16_t Length);
void UpdateDitherTableA(uint32_t *pDitherTable, uint32_t dutyCycle, uint32_t ditherV);
void UpdateDitherTableB(uint32_t *pDitherTable, uint32_t dutyCycle, uint32_t ditherV);
void UpdateIndex(void);
void TIM_DMAPeriodElapsedCplt(DMA_HandleTypeDef *hdma);
void HalfTransferComplete(DMA_HandleTypeDef *DmaHandle);
/* USER CODE END PFP */
int main(void)
{
/* MCU Configuration----------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* Configure the system clock */
SystemClock_Config();
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_DMA_Init();
MX_TIM1_Init();
/* USER CODE BEGIN 2 */
/* Initialize the first part of the DitherTable with the needed duty cycle and
dithering value */
UpdateDitherTableA(DITHER_TABLE_FIRST_PART, 0, 0);
/* Configure the TIM CCR1 update in DMA mode */
TIM1_PWM_UPDATE_DMA(&htim1, (uint32_t*) aDitherTable, 8);
/* Start the TIM1 base */
HAL_TIM_Base_Start(&htim1);
/* Starts the PWM1 signal generation */
HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
}
}
/* USER CODE BEGIN 4 */
/**
* @brief Update Dither Table - updates the first four items of aDitherTable[8]
* @param None
* @retval None
*/
void UpdateDitherTableA(uint32_t *pDitherTable, uint32_t DutyCycle, uint32_t DitherV){
uint32_t table_index;
for (table_index = 0; table_index <= 3; table_index++){
if(ditable[DitherV][table_index]){
pDitherTable[table_index] = DutyCycle + 1;
}else{
pDitherTable[table_index] = DutyCycle;
}
}//for
}
/**
* @brief Update Dither Table - updates the last four items of aDitherTable[8]
* @param None
* @retval None
*/
void UpdateDitherTableB(uint32_t *pDitherTable, uint32_t DutyCycle, uint32_t DitherV){
uint32_t table_index;
for (table_index = 0; table_index <= 3; table_index++){
if(ditable[DitherV][table_index + 4]){ //notice the +4 here...
pDitherTable[table_index] = DutyCycle + 1;
}else{
pDitherTable[table_index] = DutyCycle;
}
}//for
}
/**
* @brief Update Indexes - handles better dithering in both slopes of the triang. wave...
* @param None (with respect to original function)
* @retval None
*/
void UpdateIndex(void){
if(UpCounting == 1){
if(DitherIndex < 7){DitherIndex++;}else{
if(DCycleIndex < TIMER_PERIOD){
DCycleIndex++;
DitherIndex = 0;
}else{
UpCounting = 0;
};
};
}else{//(UpCounting == 0)
if(DitherIndex > 0){DitherIndex--;}else{
if(DCycleIndex > 0){
DCycleIndex--;
DitherIndex = 7;
}else{
UpCounting = 1;
};
};
};
};
/**
* @brief TIM DMA Period Elapse complete callback.
* @param hdma : pointer to DMA handle.
* @retval None
*/
void TIM_DMAPeriodElapsedCplt(DMA_HandleTypeDef *hdma){
if(UpCounting == 1){
UpdateDitherTableB(DITHER_TABLE_SECOND_PART, DCycleIndex, DitherIndex); //AA
}else{
UpdateDitherTableB(DITHER_TABLE_SECOND_PART, DCycleIndex, DitherIndex); //BB
}
UpdateIndex();
}
/**
* @brief Period elapsed callback in non blocking mode
* @param TimHandle : TIM handle
* @retval None
*/
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *TimHandle){
HAL_TIM_PeriodElapsedCallback(&htim1);
}
/**
* @brief DMA half conversion complete callback
* @note This function is executed when the transfer half complete interrupt
* is generated
* @retval None
*/
void HalfTransferComplete(DMA_HandleTypeDef *DmaHandle){
if(UpCounting == 1){
UpdateDitherTableA(DITHER_TABLE_FIRST_PART, DCycleIndex, DitherIndex); //CC
}else{
UpdateDitherTableA(DITHER_TABLE_FIRST_PART, DCycleIndex, DitherIndex); //DD
}
UpdateIndex();
}
-------------------------------------------
hal_msp.c
void HAL_TIM_PWM_MspInit(TIM_HandleTypeDef* htim_pwm)
{
if(htim_pwm->Instance==TIM1)
{
/* Peripheral clock enable */
__HAL_RCC_TIM1_CLK_ENABLE();
/* Peripheral DMA init*/
hdma_tim1_up.Instance = DMA1_Channel5;
hdma_tim1_up.Init.Direction = DMA_MEMORY_TO_PERIPH;
hdma_tim1_up.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_tim1_up.Init.MemInc = DMA_MINC_ENABLE;
hdma_tim1_up.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
hdma_tim1_up.Init.MemDataAlignment = DMA_MDATAALIGN_WORD; //was DMA_MDATAALIGN_HALFWORD;
hdma_tim1_up.Init.Mode = DMA_CIRCULAR;
hdma_tim1_up.Init.Priority = DMA_PRIORITY_HIGH;
if (HAL_DMA_Init(&hdma_tim1_up) != HAL_OK)
{
Error_Handler();
}
__HAL_LINKDMA(htim_pwm,hdma[TIM_DMA_ID_UPDATE],hdma_tim1_up);
}
}
note - I was not sure what is the magic of using ((uint16_t*) aDitherTable when the array was defined as uint32_t aDitherTable[16]... so I used uint32_t...
output when there is "DitherIndex" supplied to the function "UpdateDitherTable" at AA, BB, CC, DD places.
output when "0" placed instead of DitherIndex for AA and CC
output when "0" placed instead of DitherIndex for BB and DD
output when "0" placed instead of DitherIndex for AA,BB,CC and DD
