STM32f407 USART3 port does not write to com port terminal window

Hi,
I'm using STM32F407ZG (Waveshare open407Z board) with Coocox version 1.5.0.
http://www.wvshare.com/column/STM32_DevelopmentBoard.htm#Open407Z

I am using Coocox example project "ADCc_DMA.c". I coppied the c file below. It configures the USART3 port of the microController on pins PC10 and PC11.

I was able to build and run the procedure on the board.

But using the USB-to-UART board that came with the board (PL2303), the serial port "terminal window" does not show data written to it.

The driver of USB-to-UART port seems fine as the terminal window does connect to the com port. But there is just no data printing.

Can somebody help me debugging this.

Thanks,
Amin

=============================the Coocox USART example code: "ADCc_DMA.c"

/* Includes ------------------------------------------------------------------*/
#include "stm32f4xx.h"
#include "stm32f4xx_rcc.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_adc.h"
#include "stm32f4xx_dma.h"
#include "stm32f4xx_usart.h"
#include <stdio.h>

/** @addtogroup STM32F4xx_StdPeriph_Examples
  * @{
  */

/** @addtogroup ADC_ADC3_DMA
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/

  /* if you are not using the LCD, you can monitor the converted value by adding
     the variable "ADC3ConvertedValue" to the debugger watch window */

#define ADC3_DR_ADDRESS ((uint32_t)0x4001224C)

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
__IO uint16_t ADC3ConvertedValue = 0;
__IO uint32_t ADC3ConvertedVoltage = 0;

/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
void ADC3_CH7_DMA_Config(void);
void USART_Config(void);
void Display(void);

/**
  * @brief ADC convert potentimeter program
  * @param None
  * @retval None
  */
void ADCConvert_Potentiometer(void)
{
  /*!< At this stage the microcontroller clock setting is already configured,
       this is done through SystemInit() function which is called from startup
       file (startup_stm32f4xx.s) before to branch to application main.
       To reconfigure the default setting of SystemInit() function, refer to
       system_stm32f4xx.c file
     */
  USART_Config();

  /* ADC3 configuration *******************************************************/
  /* - Enable peripheral clocks */
  /* - DMA2_Stream0 channel2 configuration */
  /* - Configure ADC Channel7 pin as analog input */
  /* - Configure ADC3 Channel7 */
  ADC3_CH7_DMA_Config();

  /* Start ADC3 Software Conversion */
  ADC_SoftwareStartConv(ADC3);

  while (1)
  {
    ADC3ConvertedVoltage = ADC3ConvertedValue *3300/0xFFF;

    /* Display ADC3 converted value on Hyperterminate */
    Display();
  }
}

/**
  * @brief ADC3 channel07 with DMA configuration
  * @param None
  * @retval None
  */
void ADC3_CH7_DMA_Config(void)
{
  ADC_InitTypeDef ADC_InitStructure;
  ADC_CommonInitTypeDef ADC_CommonInitStructure;
  DMA_InitTypeDef DMA_InitStructure;
  GPIO_InitTypeDef GPIO_InitStructure;

  /* Enable ADC3, DMA2 and GPIO clocks ****************************************/
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2 | RCC_AHB1Periph_GPIOF, ENABLE);
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC3, ENABLE);

  /* DMA2 Stream0 channel2 configuration **************************************/
  DMA_InitStructure.DMA_Channel = DMA_Channel_2;
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)ADC3_DR_ADDRESS;
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&ADC3ConvertedValue;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
  DMA_InitStructure.DMA_BufferSize = 1;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Disable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
  DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
  DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
  DMA_Init(DMA2_Stream0, &DMA_InitStructure);
  DMA_Cmd(DMA2_Stream0, ENABLE);

  /* Configure ADC3 Channel7 pin as analog input ******************************/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
  GPIO_Init(GPIOF, &GPIO_InitStructure);

  /* ADC Common Init **********************************************************/
  ADC_CommonInitStructure.ADC_Mode = ADC_Mode_Independent;
  ADC_CommonInitStructure.ADC_Prescaler = ADC_Prescaler_Div2;
  ADC_CommonInitStructure.ADC_DMAAccessMode = ADC_DMAAccessMode_Disabled;
  ADC_CommonInitStructure.ADC_TwoSamplingDelay = ADC_TwoSamplingDelay_5Cycles;
  ADC_CommonInit(&ADC_CommonInitStructure);

  /* ADC3 Init ****************************************************************/
  ADC_InitStructure.ADC_Resolution = ADC_Resolution_12b;
  ADC_InitStructure.ADC_ScanConvMode = DISABLE;
  ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
  ADC_InitStructure.ADC_ExternalTrigConvEdge = ADC_ExternalTrigConvEdge_None;
  ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T1_CC1;
  ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfConversion = 1;
  ADC_Init(ADC3, &ADC_InitStructure);

  /* ADC3 regular channel7 configuration *************************************/
  ADC_RegularChannelConfig(ADC3, ADC_Channel_7, 1, ADC_SampleTime_3Cycles);

 /* Enable DMA request after last transfer (Single-ADC mode) */
  ADC_DMARequestAfterLastTransferCmd(ADC3, ENABLE);

  /* Enable ADC3 DMA */
  ADC_DMACmd(ADC3, ENABLE);

  /* Enable ADC3 */
  ADC_Cmd(ADC3, ENABLE);
}

void USART_Config(void)
{
  /* USARTx configured as follow:
        - BaudRate = 115200 baud
        - Word Length = 8 Bits
        - One Stop Bit
        - No parity
        - Hardware flow control disabled (RTS and CTS signals)
        - Receive and transmit enabled
  */
  GPIO_InitTypeDef GPIO_InitStructure;
  USART_InitTypeDef USART_InitStructure;

  /* Enable GPIO clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);

  /* Enable UART clock */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);

  /* Connect PXx to USARTx_Tx*/
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_USART3);

  /* Connect PXx to USARTx_Rx*/
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource11, GPIO_AF_USART3);

  /* Configure USART Tx as alternate function */
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* Configure USART Rx as alternate function */
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

  USART_InitStructure.USART_BaudRate = 115200;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

  /* USART configuration */
  USART_Init(USART3, &USART_InitStructure);

  /* Enable USART */
  USART_Cmd(USART3, ENABLE);

}

/**
  * @brief Display ADC converted value via USART
  * @param None
  * @retval None
  */
void Display(void)
{
  uint32_t v=0,mv=0;

  v=(ADC3ConvertedVoltage)/1000;
  mv = (ADC3ConvertedVoltage%1000)/100;
  printf(" ADC = %u,%u V \n\r",v,mv);
}

/**
  * @}
  */

/**
  * @}
  */

/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/