2014-09-22 03:49 AM
Hi everyone,
I am trying hard to make my uart4 code to working.But I am not getting anything on my hyperterminal.I am using keiluvision4.I have uploadeed th epiece of my code below.Please have a look and suggest me the chanegs required. RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE); /* Enable USART6 clock */ RCC_APB2PeriphClockCmd(RCC_APB1Periph_UART4, ENABLE); /* Configure port as pushpull, 50MHz and No pull up & down */ GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; /* Configure PC6 as alternate function */ GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10|GPIO_Pin_11; GPIO_Init(GPIOC, &GPIO_InitStructure); /* Configure PC7 as alternate function */ //GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; // GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1; // GPIO_Init(GPIOA, &GPIO_InitStructure); /* Connect PC6 to USART6_Tx*/ GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_UART4); /* Connect PC7 to USART6_Rx*/ GPIO_PinAFConfig(GPIOC, GPIO_PinSource11, GPIO_AF_UART4); /* USART6 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 */ USART_InitStructure.USART_BaudRate = 9600; 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(UART4, &USART_InitStructure); /* Enable USART */ USART_Cmd(UART4, ENABLE); while(USART_GetFlagStatus(UART4, USART_FLAG_TXE) == RESET);//while( !(UART4->SR & 0x00000040) ); USART_SendData(UART4, 'a'); thanks2014-09-22 03:59 AM
> /* Enable USART6 clock */
> RCC_APB2PeriphClockCmd(RCC_APB1Periph_UART4, ENABLE); So, is it APB1 or APB2? JW2014-09-22 04:11 AM
2014-09-22 06:46 AM
void init_USART1(uint32_t baudrate)
{
GPIO_InitTypeDef GPIO_InitStruct;
USART_InitTypeDef USART_InitStruct;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOC, &GPIO_InitStruct);
GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_UART4);
GPIO_PinAFConfig(GPIOC, GPIO_PinSource11, GPIO_AF_UART4);
USART_InitStruct.USART_BaudRate = baudrate;
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_Mode_Rx;
USART_Init(UART4, &USART_InitStruct);
USART_ITConfig(UART4, USART_IT_RXNE, ENABLE);
NVIC_InitStructure.NVIC_IRQChannel = UART4_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
USART_Cmd(UART4, ENABLE);
}
void UART4_IRQnHandler(void)
{
char data = 0;
while(USART_GetITStatus(UART4, USART_IT_RXNE)==RESET);
data=USART_ReceiveData(UART4);
while (USART_GetITStatus(UART4, USART_IT_TXE) != RESET);
USART_SendData(UART4, (uint8_t) data);
}
2014-09-22 07:44 AM
Also understand that the STM32 generates/uses CMOS levels, not RS232 levels, so you'll have to suitably interface to the PC.
Also the DISCO boards use a 8 MHz clock source, and the EVAL boards use a 25 MHz one, you need to make sure your PLL is set up for the right speed, and the define HSE_VALUE correctly reflects the clock source speed. If you need to debug further use a scope to measure the bit timing and levels, and that you have the RX/TX sense correct.2014-09-22 11:36 PM
Changing HSE value must be done not only in system_stm32f4xx.c, but MUST be changed in stm32f4xx.h
#if !defined (HSE_VALUE) #define HSE_VALUE ((uint32_t)8000000) /*!< Value of the External oscillator in Hz */