- Why did stm32 driver stop working and mouse stop serial#
- Why did stm32 driver stop working and mouse stop software#
- Why did stm32 driver stop working and mouse stop code#
However, you will still need to define the DMATransferComplete() function as shown. Note that I’ve left out some of the auto-generated Cube/HAL functions for brevity. Open main.c, and copy in the following code. Change the request to USART2_TX, and you can leave the rest of the settings at their defaults. Add a new DMA request in DMA1 (the STM32L476 has 2 DMA peripherals). You can use the same circuit from the first demo, but we won’t use the potentiometer.Ĭreate a new STM32 project, and under System Core, select DMA. We’ll create our message as a long string in memory, and then, we’ll configure our DMA to read that message, one byte at a time, to the UART transmitter. To do this, we’ll first configure the UART to output data.
Why did stm32 driver stop working and mouse stop serial#
The UART will then send out the data to our serial terminal program. So, we’ll create a rather large buffer filled with arbitrary text, and we’ll tell the DMA to send that data, one byte at a time, to the UART peripheral. One of the easiest ways to see DMA in action is to use it in conjunction with the UART. If we want to take multiple ADC readings to fill a buffer without CPU intervention, then we will need to rely on DMA. You can connect an oscilloscope probe to D2 to measure the time it takes to set up the ADC and perform one conversion, which we see is about 9.6 μs. Try turning the potentiometer knob to change the values. 0 means 0 V and 4095 means 3.3 V (or whatever you might have VREF set to). When you connect the terminal to your Nucleo board, you should see a string of numbers showing the raw ADC values.
Why did stm32 driver stop working and mouse stop code#
Run the code and bring up a serial terminal. Pretend we have to do something else for a whileīuild and debug the project. HAL_UART_Transmit(&huart2, (uint8_t*)msg, strlen(msg), HAL_MAX_DELAY)
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_10, GPIO_PIN_RESET) HAL_ADC_PollForConversion(&hadc1, HAL_MAX_DELAY) HAL_GPIO_WritePin(GPIOA, GPIO_PIN_10, GPIO_PIN_SET) * Initialize all configured peripherals */ * Reset of all peripherals, Initializes the Flash interface and the Systick. * the "License" You may not use this file except in compliance with the
Why did stm32 driver stop working and mouse stop software#
* This software component is licensed by ST under BSD 3-Clause license, * © Copyright (c) 2019 STMicroelectronics. Open main.c and change the following (note that I’ve left out the bottom portion of the auto-generated Cube functions): The mbed Nucleo-L476RG page has a great pinout diagram, if you need help finding which pin goes where on the Nucleo board. The ADC configuration settings can stay at default.
Change IN5 to IN5 Single-ended, which allows us to use PA0 as an ADC pin.
Under Categories, go to Analog, and select ADC1. Change PA10 (which is connected to header pin D2) to GPIO_Output. Start a new project in STM32CubeIDE with C. Getting the STM32 to take 1 ADC reading is relatively straightforward. Note that any Nucleo board may be used, but steps are shown for the Nucleo-L476RG.įor the few demonstrations that follow, we will need a Nucleo board (I’m using a Nucleo-L476RG) and a potentiometer connected to A0: You will need the following components to complete this tutorial: If you need to take only one ADC reading, setting up the DMA controller is likely not worth the extra CPU cycles. We can configure to the DMA to do just that:īecause of the overhead involved in setting up the DMA, using it is usually only worthwhile if you need to move long, contiguous streams of data. There is a small amount of overhead involved in setting up the DMA, but once it’s done, the CPU can work on other things while the DMA moves data.įor example, let’s say that we wanted to collect data from the ADC and store it to a large buffer in memory. Luckily for us, many modern microcontrollers (and microprocessors) include a DMA controller, which is a separate peripheral that can be configured to automatically send data from one peripheral to another (including memory). If we start working with large amounts of data, we can quickly overwhelm the CPU if it has to touch every byte of data.
Each time we want to send data from one peripheral to the other, the CPU must read data from that peripheral’s data register (or memory) and send it to another peripheral (or memory). We have a number of peripherals controlled by the central processing unit (CPU). We might normally think about memory transfer in a microcontroller in this (overly simplified) fashion: If every byte has to pass through the CPU, you’ll quickly run out of cycles to do useful things! That’s where the separate direct memory access controller comes in-it can help transfer data without any code running. If you are working with large amounts of data, whether from the ADC or trying to pipe the contents of memory over the UART, you might find that your processor quickly gets bogged down.
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