Posted on August 22, 2014 at 17:09 Hello everybody!
It's not my first experience with USART but this time I have an unsolvable problem
🙂 I try to use USART1 TX with the pin PA9 but I can't send datas. The pin PA9 always outputs 1.1V and never switch. When I configure the pin as a standard GPIO, I can set it to high and low level (0V and 3.3V) without problems.
I think this is maybe due to the fact I use the USB and the pin PA9 can be used as the VUSB input.
This my code for the USART1 config:
void
USART_Config(
void
)
{
RCC_APB1PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
// USART1 clock
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
// GPIOA clock
GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_USART1);
// PIN A9 linked to the USART1
// Tx GPIO init
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 ;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
// alternate function!
GPIO_InitStructure.GPIO_OType = GPIO_OType_OD ;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
// USART init:
// Vitesse du MIDI = 31250
USART_InitStructure.USART_BaudRate = 31250;
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_Tx;
USART_Init(USART1, &USART_InitStructure);
USART_Cmd(USART1, ENABLE);
}
Then to send a data I simply use
USART_SendData(USART1, data_out);
Thanks a lot for your help!
#rtfs
