Cannot get UART interrupt to fire with standard peripheral lib

[Alexander Hoffman]

Posted on February 14, 2018 at 16:41

Hi all,

I am working on a project based around an old comms stack that uses the standard peripheral library, which i'm not that familiar with. I have been trying for a good couple of days now to get the UART rx interrupt to fire without luck. I have been basing my work off of the example here 

http://pandafruits.com/stm32_primer/stm32_primer_uart.php

 . I am able to send over UART but cannot seem to receive via interrupt.

I am initilizing USART1 and 3, 3 being part of the exsisting comms stack I am trying to implement in my project, my code for initilizing USART is as follow

void serial_init_1(unsigned int baud)

{ USART_InitTypeDef USART_InitStructure; GPIO_InitTypeDef GPIO_InitStructure;

// Enable USART1 and GPIOA clock */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);

/* Configure USART1 Tx (PA.09) as alternate function push-pull */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOA, &GPIO_InitStructure);

/* Configure USART1 Rx (PA.10) as input floating */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_Init(GPIOA, &GPIO_InitStructure);

USART_InitStructure.USART_BaudRate = baud;

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_Init(USART1, &USART_InitStructure);

/* Enable the USART1 Receive interrupt: this interrupt is generated when the

USART1 receive data register is not empty */ USART_ITConfig(USART1, USART_IT_RXNE, ENABLE); /* Enable USART1 */ USART_Cmd(USART1, ENABLE); // NVIC_EnableIRQ(USART1_IRQn);}

Then the NVIC as follows

nvic_initialisierung(USART1_IRQn | USART3_IRQn);

void nvic_initialisierung(uint16_t IRQ)

{ NVIC_InitTypeDef NVIC_InitStructure; //create NVIC structure NVIC_InitStructure.NVIC_IRQChannel = IRQ; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);// NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);}

I have then defined 

void USART1_IRQHandler(void)

{}

But it is never reached.

Any advice and or links to solid examples would be appreciated. I have tried many slight variations of what is above but nothing seems to work.Cheers#stm32 #standard-peripheral-library #uart

[Tesla DeLorean]

Posted on February 14, 2018 at 17:32

If using a .CPP file (or C++ compilation) use

extern 'C' void USART1_IRQHandler(void)

{

  // need code here, lest processor stops executing

}

What STM32 part?

Does the USART work in polling mode, ie you transmit a loop of 'U' chars, or you echo back received data

[T J]

Posted on February 15, 2018 at 03:34

I have mastered the Uart dma stuff now, do you know about the cube ?

I use the Cube to initialise 3 serial ports and many other periherials,

in main.c every thing is already done,

you just need to adjust some callbacks.

[Alexander Hoffman]

Posted on February 16, 2018 at 09:59

Thanks for the responses. Unfortunately I need to use the standard peripheral libraries and not the HAL libraries that I normally work with. UART in HAL is so much easier.

Turvey.Clive.002

it's not a cpp file and I have not tried polling because I need to get it working with interrupts. I know that the UART physically works as I originally tried porting the project into HAL but that proved to be a much more challenging process, none the less the UART worked in HAL no problem. I am not sure what I am missing.

[Tesla DeLorean]

Posted on February 16, 2018 at 10:17

Make sure the USART isn't flagging any errors (parity, framing, etc) which will need to be cleared.

Not going to get interrupts if USART isn't receiving anything, the one-minute sanity check is to have a tight polling loop echoing data back to a terminal.

Its not a bitvector, ORing an index number isn't likely to get a valid number for either interrupt.

nvic_initialisierung(USART1_IRQn | USART3_IRQn);

nvic_initialisierung(USART1_IRQn);

nvic_initialisierung(USART3_IRQn);

[AvaTar]

Posted on February 21, 2018 at 10:51

// Enable USART1 and GPIOA clock */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);

Are you sure about that ?

For a F303 example I have, GPIO is on AHB, not APBx:

    /* UART1 on PC4,PC5 */

    /* Enable GPIO clock */

    RCC_AHBPeriphClockCmd (RCC_AHBPeriph_GPIOC, ENABLE);

    /* Enable USART clock */

    RCC_APB2PeriphClockCmd (RCC_APB2Periph_USART1, ENABLE);

[Alexander Hoffman]

Posted on February 21, 2018 at 10:04

Thanks I'll give this a try and check back.

Cheers

[henry.dick]

Posted on February 21, 2018 at 12:50

You didn't enable uart1 nvic - you did uart3 instead.

Interrupts on those parts involve the flag, the enable bits, the nvic specific to that peripheral and the global irq.

You are almost there.