https://www.robolabor.ee/homelab/ 2026-04-17T00:33:00+00:00 https://www.robolabor.ee/homelab/ https://www.robolabor.ee/homelab/lib/tpl/arctic/images/favicon.ico text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/adc?rev=1595235600&do=diff Analog-to-digital Converter Analog-to-digital converter (ADC) transforms an analog voltage value to a digital value. The allowed voltage range on an ADC input of an AVR microcontroller is 0 to 5.5 V. The size of the digital value is 10 bits, but its precision is ±2 units. The error may be even larger, if the microcontroller's supply voltage is not protected from interference. AVR has a separate voltage supply and comparison voltage pin for ADC. The separate supply voltage helps to cut down the … text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/architecture?rev=1595235600&do=diff Architecture AVR has an internal 8-bit data bus, through which the data is moved between the arithmetic logic unit (ALU), status register (SREG), program counter (PC), random access memory (SRAM) and peripherals. The program, an array of commands that is executed in the ALU, comes from an address in the flash memory, specified by the program counter. The ALU has 32 8-bit general purpose registers, which are used as operands when carrying out instructions. text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/clock?rev=1595235600&do=diff Clock As with most digital electronics, an AVR also works at a constant frequency. A constant frequency assures the reliability of data exchange throughout the device. There are several methods for generating a clock signal for an AVR. Internal RC Oscillator text/html 2026-02-19T11:31:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/dac?rev=1771493460&do=diff Digital-to-analog converter Digital-to-analog converter (DAC) converts a digital signal into an analog voltage. The AVR xmega DAC output voltage can range from 0 to the reference voltage. The DAC digital input resolution is 12-bit and the throughput is up to 1 million conversions per second (MSPS) per channel. text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/external_interrupts?rev=1595235600&do=diff External Interrupts External interrups are one of the most simple peripheral functions. Typically AVRs have 1 to 8 special pins, which are used to cause interrupts in the program when their logical value changes or they are at a certain state. Since this function is usually used to monitor external logical signals, these pins are called external interrupt pins. text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/interrupts?rev=1595235600&do=diff Interrupts Interrupts in AVR can be caused by counters, communication interfaces, analog-to-digital converters, comparators, special input-output pins and several other functions, depending on the controller. Any interrupt can be allowed or disallowed by the unit that generates it. Regardless of the interrupt being allowed or disallowed, there is a 1-bit field (interrupt flag) in the corresponding unit of the controller, which is marked as true when the interrupt condition is fulfilled. If the … text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/introduction?rev=1595235600&do=diff Introduction AVR is a series of 8-bit RISC microcontrollers produced by Atmel. AVR follows Harcard architecture and therefore has separate program and data memory. For the program it has an internally overwriteable flash memory, for data there are static (SRAM) and EEPROM memory. Controller's frequency is usually up to 16 text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/io?rev=1595235600&do=diff Digital Inputs/Outputs All the buses on an AVR are both readable and writable, if they are used in the default logical input/output (I/O) mode. AVR buses are named as letters from the beginning of the Latin alphabet: A, B, C etc. Some AVRs might not have bus A, though, if bus B exists. Each bus is 8-bit and each bit usually has its own pin on the controller. Pins are counted with numbers starting from zero. For both directions on the bus, there are two separate registers. In addition, there is … text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/registers?rev=1595235600&do=diff Registers One of the toughest things for beginners to understand in a microcontroller is typically a register. When dealing with microcontrollers, it is impossible to get by without knowing what this device is. This book is in no way different, as the reader is also expected to familiarize him/herself with the concept of a register and therefore the following text will try to explain it in simple enough terms so that even a beginner can grasp the idea of a register. text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/timers?rev=1595235600&do=diff Counters/Timers Counters, which in some sense can be called timers, are one of the most important sub-functions of a microcontroller. These enable to precisely time processes, generate signals and count events. A counter converts the number of input cycles to a binary value using an array of triggers. The maximum number of counted cycles depends on the length of this array, and this is marked by the length of the binary code. AVR has 8- and 16-bit counters. If a timer has reached its maximum va… text/html 2020-07-20T12:00:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.robolabor.ee/homelab/en/avr/usart?rev=1595235600&do=diff USART USART is a universal synchronous serial interface; UART, is a simplified version - universal asynchronous serial interface. The difference being that USART also uses a clock signal line to synchronize data, but UART only uses data lines. AVR's USART allows the use of full duplex communication, 5- to 9-bit data words (8-bit word = byte), 1 or 2 stop bits, three parity modes and a wide variety of baud rates. AVR microcontrollers typically have up to 2 USART interfaces, although some may hav…