4/13/2021 0 Comments Stm32 Uart Interrupt Enable
How to Send Data and Receive Data on UART port And Application of UART Communication in Embedded Application.The DMA interrupt overhead also doesnt scale up when you increase buffer size, so sending 70 bytes in a packet instead of 7 would reduce the overhead to 0.6.
Stm32 Uart Interrupt Enable How To Use DirectWe will show how to use direct mode, interrupt-based mode and DMA-controlled mode and will use a logic analyzer to compare the precise timings of various events.We will use the Nucleo-F410RB board that has the STM32F410RB chip.We will begin with a simple program that will read bytes via UART and echo them back in groups of 4. Pull GPIONOPULL; HALGPIOInit ( GPIOA, GPIOInitStructure); GPIOInitStructure. Mode GPIOMODEAFOD; HALGPIOInit ( GPIOA, GPIOInitStructure); sUARTHandle. You can find the GPIO pin numbers and the alternate function numbers corresponding to the UART interface on your device by searching the datasheet for the Alternate Function Mapping section: For STM32F410RB connecting UART2 to pins PA2 and PA3 requires enabling alternate function 7. If you are using VisualGDB Custom Edition, simply enable the Raw Terminal in VisualGDB Project Properties and it will show a terminal window inside the Visual Studio window. Try typing some text in the terminal window and see how after every 4 characters the program echoes them back. First of all, modify your code to continuously output testrn and use GPIOC10 to signal the lifetime of the HALUARTTransmit() function. Connect your second board to your computer, start Analyzer2Go and select the board type. See how the HALUARTTransmit() function (red) is active during the entire transmission (blue). You can click the set clock period button to highlight individual zeroes and ones. While the transmission is active, the program cannot do anything else and has to wait for it to complete. We will now use the interrupt-based transmission to free up some of the CPU cycles. Then check the call stack: You can see how the UART interrupt got invoked when the main() function was already running HALDelay(). The USART2IRQHandler() handler called the HALUARTIRQHandler() and the HALUARTIRQHandler() in turn called the HALUARTTxCpltCallback() once it determined that the last byte got transmitted. Then add the C11 and C12 signals to Analyzer2Go and make another recording. ![]() Finally, the HALUARTTxCpltCallback() (orange signal switching to 0) is called once the last byte was physically sent. You can measure the overhead of the UART interrupts by comparing the byte transmission period to the width of the ISR pulse. For STM32F410RB the overhead is 12 out of 96 microseconds (12.5) regardless of the buffer size. In this mode the DMA controller will automatically feed the entire buffer to the UART byte-by-byte and only raise an interrupt once the entire buffer is sent. Use the DMA Request Mapping table in your devices reference manual (not datasheet) to get the correct numbers. See how now the DMA interrupt is only called twice per the entire transmission (once for each half of the buffer): If you measure the interrupt overhead now you should get 41 microseconds out of 670 (for the entire packet) or 6.
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