Posted on May 17, 2011 at 12:52Hallo everybody,
I am new with the Cortex M3 and have some problems using the UART. I can´t see any output on Windows Terminal. I use CrossStudio for ARM with Olimex ARM-USB-OCD and this is the source codes :
void RCC_Configuration(void)
{
RCC_DeInit();
// 2. Enable ext. high frequency OSC
RCC_HSEConfig(RCC_HSE_ON);
// wait until the HSE is ready
while(RCC_GetFlagStatus(RCC_FLAG_HSERDY) == RESET);
// 3. Init PLL
RCC_PLLConfig(RCC_PLLSource_HSE_Div1,RCC_PLLMul_9); // 72MHz
RCC_PLLCmd(ENABLE);
// wait until the PLL is ready
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);
// 4. Set system clock divders
/* RCC_USBCLKConfig(RCC_USBCLKSource_PLLCLK_1Div5); */
RCC_HCLKConfig(RCC_SYSCLK_Div1); // AHB Clock = 72 MHz
RCC_PCLK2Config(RCC_HCLK_Div1);
RCC_ADCCLKConfig(RCC_PCLK2_Div8); // ADC Clock = 8 MHz
RCC_PCLK1Config(RCC_HCLK_Div2);
// Flash 1 wait state
*(vu32 *)0x40022000 = 0x12;
// 5. Clock system from PLL
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
while(RCC_GetSYSCLKSource() != 0x08)
{
}
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO | RCC_APB2Periph_ADC1 |RCC_APB2Periph_AFIO | RCC_APB2Periph_USART1, ENABLE);
}
int main (void)
{
#ifdef DEBUG
debug();
#endif
/* System clocks configuration ---------------------------------------------*/
RCC_Configuration();
// Configure PA.9 (USARTT1_TX) as output Open Drain Output Alternate-Function
GPIO_ResetBits(GPIOA,GPIO_Pin_9);
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_OD;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStruct);
USART_Configuration();
USART_Cmd(USART1, ENABLE);
while(1)
{
USART_SendData(USART1, 0xaa);
while(!USART_GetFlagStatus(USART1, USART_FLAG_TXE))
{
}
while(!USART_GetFlagStatus(USART1, USART_FLAG_TC))
{
}
}
}
/*******************************************************************************/
void USART_Configuration(void)
{
USART_InitTypeDef USART_InitStruct;
/* Configure -------------------------*/
USART_InitStruct.USART_BaudRate = 9600; /* 9600 Baud */
USART_InitStruct.USART_WordLength = USART_WordLength_8b;
USART_InitStruct.USART_StopBits = USART_StopBits_1;
USART_InitStruct.USART_Parity = USART_Parity_No ;
USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStruct.USART_Mode = USART_Mode_Tx;
/* USART_InitStruct.USART_Clock = USART_Clock_Enable;
USART_InitStruct.USART_CPOL = USART_CPOL_Low;
USART_InitStruct.USART_CPHA = USART_CPHA_1Edge;
USART_InitStruct.USART_LastBit = USART_LastBit_Disable; */
USART_Init(USART1, &USART_InitStruct);
}
I have tested the output of UART Tx Pin with oscilloscope but there is output signal. Before i have already test program loading by the simple ''blinky'' program and it´s ok.
I really have no idea. Could someone help me ? thank u
