Posted on June 01, 2015 at 12:07
>Are you able to see the PWM signal on the pin? Which pin specifically? Your code lacks defines.
>Are you able to modulate the PWM with the DMA buffer? >Is it stuck in the DMA TC while() loop? Here my defines: #define DATA_PIN GPIO_Pin_4 #define DATA_GPIO_PORT GPIOB #define DATA_GPIO_CLK RCC_AHBENR_GPIOBEN When I set request event CC1 I see PWM (attached pictures). I modulate PWM form DMA buffer, but I have one troble with this (see marked osciloscope diagram). Timer get 2 pulses for one period and two signals is sticking (I think that happen 'couse I set CC1). I want to initialize request event update but then I lacks in while() loop. while(!DMA_GetFlagStatus(DMA1_FLAG_TC4)); I >You probably need to initialize memaddr to zero. Nine or Eight bits? Yes, I set 8 bits to zero. >Do you need to turn this on/off, or can you send a continuously modulated stream of bits? If you call Transmit9Bit() it send 8 bit (pay no attention to the function name).#include ''2WireInterface.h''
#define buffersize 8
/** @defgroup 2WireInterface_Private_Variables
* @{
*/
static __IO uint16_t LED_BYTE_Buffer[buffersize+1];
/**
* @}
*/
/**
* @brief Initializes interface.
* @param None
* @retval None
*/
void Init2WireInterface(void)
{
RCC_Configuration();
Interface_GPIOInit();
Timer3_Init();
InitDMA();
}
/**
* @brief Transmit 9 Bit.
* @param IntensityColor,
*
@arg Intensity
@arg Color
* coordinate.
* @retval None
*/
void Transmit9Bit(IntensityColor_TypeDef IntensityColor, uint8_t coordinate)
{
/*coordinate = coordinate <<
2
;
if (IntensityColor)
{
coordinate = (coordinate) || 0x001;
}
else
{
coordinate = (coordinate) || 0x003;
}*/
uint16_t
memaddr
=
0
; // reset buffer memory index
while (memaddr < buffersize)
{
if ( (coordinate<<memaddr) & 0x80 )//0x100
{
LED_BYTE_Buffer[memaddr] = 96-1; // compare value for logical 1
}
else
{
LED_BYTE_Buffer[memaddr] = 48-1; // compare value for logical 0
}
memaddr++;
}
LED_BYTE_Buffer[buffersize] = 0;
//TIM_GenerateEvent(TIM3, TIM_EventSource_Update);
//TIM_DMACmd(TIM3, TIM_DMA_Update, ENABLE);
DMA_SetCurrDataCounter(DMA1_Channel4, buffersize); // load number of bytes to be transferred
DMA_Cmd(DMA1_Channel4, ENABLE); // enable DMA channel 4
TIM_ClearFlag(TIM3, TIM_FLAG_Update);
TIM_Cmd(TIM3, ENABLE); // enable Timer 3
//TIM_CtrlPWMOutputs(TIM3, ENABLE);
while(!DMA_GetFlagStatus(DMA1_FLAG_TC4)); // wait until transfer complete
TIM_Cmd(TIM3, DISABLE); // disable Timer 3
//TIM_DMACmd(TIM3, TIM_DMA_Update, DISABLE);
//DMA_Cmd(DMA1_Channel4, DISABLE); // disable DMA channel 4
DMA_ClearFlag(DMA1_FLAG_TC4); // clear DMA1 Channel 4 transfer complete flag
}
/**
* @brief Enables the AHB peripheral clock.
* @param None
* @retval None
*/
static void RCC_Configuration(void)
{
/* Enable the GPIO_Interface Clock */
RCC_AHBPeriphClockCmd(DATA_GPIO_CLK, ENABLE);
/* Enable the TIM3_Interface Clock */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
/* Enable the DMA_Interface Clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
}
/**
* @brief Initializes the GPIOx peripheral.
* @param None
* @retval None
*/
static void Interface_GPIOInit(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Configure the GPIO_Interface pin */
GPIO_PinAFConfig(DATA_GPIO_PORT, GPIO_PinSource4, GPIO_AF_1);
GPIO_InitStructure.GPIO_Pin
=
DATA_PIN
;
GPIO_InitStructure.GPIO_Mode
=
GPIO_Mode_AF
;
GPIO_InitStructure.GPIO_OType
=
GPIO_OType_PP
;
GPIO_InitStructure.GPIO_PuPd
=
GPIO_PuPd_NOPULL
;
GPIO_InitStructure.GPIO_Speed
=
GPIO_Speed_50MHz
;
GPIO_Init(DATA_GPIO_PORT, &GPIO_InitStructure);
}
/**
* @brief Initializes the TIM3 peripheral.
* @param None
* @retval None
*/
static void Timer3_Init(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period
=
192
-1;
TIM_TimeBaseStructure.TIM_Prescaler
=
1
;
TIM_TimeBaseStructure.TIM_ClockDivision
=
TIM_CKD_DIV1
;
TIM_TimeBaseStructure.TIM_CounterMode
=
TIM_CounterMode_Up
;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode
=
TIM_OCMode_PWM1
;
TIM_OCInitStructure.TIM_OutputState
=
TIM_OutputState_Enable
;
TIM_OCInitStructure.TIM_Pulse
=
0
;
TIM_OCInitStructure.TIM_OCPolarity
=
TIM_OCPolarity_Low
;
TIM_OC1Init(TIM3, &TIM_OCInitStructure);
}
/**
* @brief Initializes the DMA Channel4.
* @param None
* @retval None
*/
static void InitDMA(void)
{
/* DMA1 Channel4 Config */
DMA_DeInit(DMA1_Channel4);
DMA_InitTypeDef DMA_InitStructure;
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(TIM3->CCR1); // physical address of Timer 3 CCR1
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)&(LED_BYTE_Buffer[0]); // this is the buffer memory
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST; // data shifted from memory to peripheral
DMA_InitStructure.DMA_BufferSize = buffersize;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; // automatically increase buffer index
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
DMA_InitStructure.DMA_Mode = DMA_Mode_Normal; // stop DMA feed after buffer size is reached
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA1_Channel4, &DMA_InitStructure);
//DMA_Cmd(DMA1_Channel4, ENABLE);
/* TIM3 Update DMA Request enable */
TIM_DMACmd(TIM3, TIM_DMA_Update, ENABLE);
}
/**
* @}
*/
/*****END OF FILE****/