Projects for the amateur radio engineer. Hardware, software, electronics and test equipment for the amateur community.
by Peter Baier (DK7IH) Abstract We intended to explore, if it is possible to directly frequency modulate a Direct Digital Synthesizer (DDS) with a given sine wave by using a fast microntroller (MCU) and optimized data transfer. The goal was to achieve this by using widely available radio amateur hardware, i. e. low cost equipment.…
Abstract This uni of our online tutorial will cover the implementation, configuration and usage of I2C communication with the STM32F4 MCUs. Later we will show practical examples, that can be used for driving an SH1106 OLED display for example or a 24C65 external EEPROM. I2C basics I2C (spoken “I square C” for inter-integrated circuit) has…
by Peter Baier (DK7IH) Abstract In this article we will discuss pulse width modulation (PWM), how the respective signals are produced and how we can use them to control motor, light bulbs, LEDs etc. PWM in short When current consuming devices like motors, light bulbs, LEDs etc. have to be controlled concerning their intensity you…
by Peter Baier (DK7IH) Abstract Today’s lesson will cover a topic that the software developer will encounter sooner or later: The need to decode the signals from a rotary encoder. We will discuss that and deliver a simple and easy-to-use solution for this problem. Theory A rotary encoder is a set of two mechanical or…
by Peter Baier (DK7IH) Abstract This unit will cover the basic usage of the Analog-Digital-Converter (ADC) in the STM32F4 MCU. We will develop a simple procedure to read multiple ADC values from various input pins and have these data ready for further processing. ADC in STM32F4 in brief The Analog-Digital-Converter in the STM32F4 MCU uses…
by Peter Baier (DK7IH) SPI (serial peripheral interface) is a communication interface between electronic devices like microcontrollers, displays, DDS generators and many other electronic circuits. It is widely used, thus the manufacturers of microcontrollers have implemented predefined SPI functions into their hardware. On the other hand, it is possible (and easy) to write these functions…
by Peter Baier (DK7IH) Abstract This unit will cover the basic usage of timers and related interrupts, a crucial topic in the world of microcontrollers. Introduction The STM32/Arm Cortex(R)-M4 MCUs contain a large number of timers: Basic timers General-purpose timers Advanced-control timers There are up to 14 timers in an STM32-MCU that are fully independent…
by Peter Baier (DK7IH) Abstract In this chapter of our online course we will see how Alternate Functions (AF) in the STM32 MCUs are programmed and used. Later we will measure the clock frequency by activating the respective “AF” and put out main clock frequency via an external pin to measure it. Alternate Functions in…
by Peter Baier (DK7IH) With AVRs clocking was easy. Just set some fuse bits (but the right ones with the right values!!!!) , install external clock (optional) and go for it! With STM32s it is, as you might think, its alittle bit more complex. Various sources for the clock signal In the STM32F4 MCU there…
Abstract In this lesson we will talk about port configuration in the STM32F4 MCU. First a closer look to the registers will be taken and then we will cover first output port configuration. By the end of this lesson input port config and usage will be covered. Handling registers When reading and writing data in…