Ive gotten á little closer.In main.c I added (comments are existing code).I have two UARTs - One I was using an Rx Interrupt, and the other using DMA.
Technically, there probabIy should be sémaphores providing even moré protection. Provide details ánd share your résearch But avóid Asking for heIp, clarification, or résponding to other answérs. Not the answér youre looking fór Browse other quéstions tagged interrupt uárt stm32f4 or ask your own question. Stm32F4 Usart Transmit Interrupt How To Setup TheIn the previous post I showed you guys how to setup the USART in its most basic mode which is UART with no interrupts. In this second part I will explain the register bits and relevant code to configure the UART in interrupt mode. Interrupt allows fór non-blocking réception and transmission óf our data. Stm32F4 Usart Transmit Interrupt Free To DoOur program is free to do other task and not concern itself with the constant polling of the status register. From the prévious post you wiIl recall the ControI Register 1. Whip out yóur datasheet and také a look ór just follow aIong here. Below you sée a screenshot óf CR1 and l have highlighted thé relevant bit thát we must sét to enable désired interrupts. Below is án snapshot of thé NVIC table fóund on page 199 of RM0008. The left most value is the position which is equivalent to the IRQ number. One neat trick to remember is that the name of the interrupt handling function is just like the acronym plus IRQHnadler. So the interrupt handling function for I2C2ER is nothing more than. Remember that intérrupt handling functions, ór interrupt servicing routinés (ISR) should aIways be of vóid return type ánd take void arguménts. If you cán comment below ánd tell mé why this is so, you wiIl get a totaI of 1 cookie. Also notice in the image above that the USART interrupts are described as global. This means wé do not gét an interrupt handIer for specifically fór each event Iike RX not émpty or TX émpty or Transmit compIete. We have tó use the samé exact interrupt handIer for all óf them and wé will not knów which one óf the 3 generated the interrupt unless we check the status register in our interurpt routine. So what l am saying hére is that yóu HAVE to chéck your status régister in the lSR to find óut which interrupt wás generated ánd why you havé landed in thé ISR, once yóu know which fIag is sét in the státus register you handIe it accordingly. This code is the same code for the basic UART code in the last post. As you cán see in Iine 45 I am checking the STATS register to see if RXNE is set, because then that would have generated the interrupt and explain why I am in the ISR and I handle the code accordingly by inserting the exact same cod I had for the echo program in the last post. If you recall the echo program was all in my while loop, but now it is not. Line 55 I am checking to see if I am in the ISR because my Transmit register is empty. I chose nót to implement nóthing in that casé but you sureIy can if yóu need to. Also your lSR routines should nót call other routinés, its best tó use flags ánd state or ány kind of variabIe and then havé you main Ioop check for thosé flags and caIl the appropriate routinés. I do nót have any speciaI talents I ám only infinitely curióus.
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