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NUCLEO F401RE LED BLINK SERIAL
NUCLEO F401RE LED BLINK SOFTWARE
NUCLEO F401RE LED BLINK CODE
NUCLEO F401RE LED BLINK SERIES

On-board connections will be utilized and the include the following: There will be no need for external connections.

NUCLEO F401RE LED BLINK CODE

Note that if the code on the git repo is slightly different then it means that it was modified to enhance the code quality or accommodate any HAL/Rust updates.

Familiarity with the basic template for creating embedded applications in Rust.Īll the code presented in this post in addition to instructions for the environment and toolchain setup are available on the apollolabsdev Nucleo-F401RE git repo.

To understand the content of this post, you need the following: Again, I will not be using interrupts and instead would be polling a timer/counter for the elapsed time. This will make the delay more deterministic and scalable among different platforms. In this post, I will be enhancing the previous code by instead leveraging a timer/counter peripheral to manage the delay.

NUCLEO F401RE LED BLINK SOFTWARE

It was mentioned as well that using software is not ideal to create delays as it does not scale and hardware methods (ex. Even delay was created algorithmically, meaning that there was a piece of code (loop) that generated the needed delay. In the previous post, the focus was on the GPIO peripheral and I had controlled the rate of flashing of an LED connected to a GPIO output using a button connected to a GPIO input. In this post, I will enhance the GPIO button-controlled blinking project in my previous post by using a timer/counter peripheral instead. If you liked this post, please make sure you subscribe to the newsletter here to stay informed about new blog posts. Please be aware that certain concepts in newer posts could depend on concepts in prior posts.

NUCLEO F401RE LED BLINK SERIES

While doing nothing but flashing a led that is of course OK, but typically one would want the processor to do "other things" and if that is the case the actual LED frequency will be even more unpredictable.This blog post is the second one of a multi-part series of posts where I explore various peripherals in the STM32F401RE microcontroller using embedded Rust at the HAL level. While that is running, the processor is tied up in doing "nothing". Sure, it will only be "off" by a few micro seconds, but it will be off! In reality, this approach has at least two problems.įirst of all, the call of both HAL_GPIO_TogglePin and HAL_Delay are not single instructions, so the actual time spend in the loop will be "a tiny bit" longer than 500 ms resulting in a frequency which is slightly below the intended 1 Hz. I made the claim earlier that this approach was generally misguided and that is part of the problem. The keyword in the above description is "approximately". The result will be approximately 1 blinks per second: It will toggle the led, not caring what the previous state was, and then wait for 500 ms. The approach is simple and easily understood. Using Stm32CubeIde and it's HAL libraries, the main loop will look something like:

In this approach, the led is simply toggled in the main loop of the program, with an appropriate delay. This approach, while quite misguided, is often seen in examples, particularly Arduino based ones. This is the frequency at which the timers will operate (in this case 72 MHz - remember this value for later examples). Also important to notice is the value of the APB1 Timer Clocks. The important values here is the value of the external crystal (in this case 8 MHz), the value of HCLK, which is the frequency the processor will run at. Second step is to configure the CPU to enable the external crystal:įinal step is to configure the various clocks:

NUCLEO F401RE LED BLINK SERIAL

First step I configure the Serial Wire debug (including the trace): When starting a new project in Stm32CubeIde, I generally go through some common settings. Stm32CubeMx is used to "configure" the processor. These are discussed in the following sections.įor these examples, I will be using ST's Stm32CubeIde, which includes Stm32CubeMx. Using the STM32 HAL from ST there are a number of different ways to blink a LED.