const GPIO_ports led_port = GPIO_PORT_B const uint8_t led_pin = 3 // Nucleo-f042k6: Port B, pin 3. All it does is read the input register of the GPIO pin and adjust an output depending on the input value, but that still gives one the power to turn a LED on or off at will: It’s more basic than the traditional ‘Blinky’ example, as it only uses the Reset & Clock Control (RCC) registers and basic GPIO peripheral. Probably the most basic useful example would be what I affectionately call ‘ Pushy‘ in my Nodate STM32 framework. Ultimately the main function is called, akin to when the operating system of a PC is started after the BIOS has finished setting up the environment. Initializing the stack pointer (SP) is essential, as well as copying certain parts of the ROM into RAM and initializing a number of registers.
Nucleo f401re reference manual code#
Generally, in this start-up code one wants to do the essentials, such as setting up the interrupt vector table and the basic contents of specific registers. Whatever happens next is up to this code. In the case of an MCU this is the code stored starting at a specific offset in the (usually) integrated read-only memory (ROM).
You still got at least one CPU core which is initialized once external power has stabilized, at which point start-up firmware is read from a fixed location. Let’s take a look at how bare-metal STM32 programming works, and make the most basic example run, shall we? Like a PC, only differentįundamentally, there is little difference between a microcontroller and a full-blown Intel or AMD-based computer.
Nucleo f401re reference manual manuals#
Yet where is the fun in that, when at the end of the day one is still fully dependent on that framework’s documentation and its developers? More succinctly, if the contents of the STM32 reference manuals still look like so much gibberish, does one really understand the platform? Why, indeed?ĭefinitely, one could use any of the existing frameworks to program an STM32 MCU, whether the ST HAL framework, plain CMSIS, or even something more Arduino-flavored. If your first response to that question wasn’t a panicked dive towards the nearest emergency exit, then it might be that that question has piqued your interest. Some may ask why you’d want to program a Cortex-M microcontroller like the STM32 series using nothing but the ARM toolchain and the ST Microelectronics-provided datasheet and reference manual.
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