Tag Archives: Atmega8

Atmel ATmega8 – A World-Famous Microcontroller Created By Two Annoyed Students

AVR is a family of microcontrollers developed by Atmel beginning in 1996. These are modified Harvard architecture 8-bit RISC single-chip microcontrollers. The Atmel AVR core combines a rich instruction set with 32 general purpose working registers. Atmel’s ATmega8 comes from the AVR line of microcontroller and it is a gem of the modern maker movement. It is used as the heart of the first generation of the Arduino board to be widely adopted by electronics hobbyists. Countless creative projects are designed with those cheap yet powerful chips.

ATmega8 was originally developed in the early 1990s by two students at the Norwegian University of Science and TechnologyAlf-Egil Bogen, and Vegard Wollan. Microcontrollers are different from microprocessors in terms of built-in memory and I/O peripherals. They typically have their own onboard program memory and RAM, rather than relying on external chips for these resources.

When Bogen and Wollan were in university, they faced trouble in following the steep learning curve of the complex instruction sets for microprocessors. Most of the processors used in those days were CISC (Complex instruction set computer) based. They wanted to design a RISC (reduced instruction set computer) based microcontroller with an aim in mind to create something that would be easy to program and relatively powerful. Bogen explained in a YouTube video,

I found them very hard to us. The learning curve to get to use them was hard; I found the development tools crappy. And also I saw that the performance of the products was not where I wanted it to be.

Bogen
Alf-Egil Bogen – one of the creators of the AVR core

Computers, that are typically used on the day-to-day basis, use Von Neumann architecture. In this architecture, programs are loaded into the RAM first and then executed from the same. AVR uses the Harvard architecture, in which program memory and working RAM are kept separate, thus enables faster execution of instructions. The first prototype of AVR used ROM, which is not re-writeable, as the program memory. Later Atmel added easily programmable (and reprogrammable) flash memory to the processor core. The first commercial AVR chip, the AT90S8515, was released in 1996. Wollan says in a video,

instructions and stuff were things we were actually thinking of from the very beginning to make it efficient and easy to use from a high-level point of view

Wollen
Vegard Wollen – another creator of AVR

ATmega8 Thermocouple Thermostat

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morethanuser.blogspot.com has published a thermocouple thermostat based on ATmega8 and  MAX31855KASA Thermocouple to digital converter IC from Maxim.

Here is a circuit, I used popular thermocouple type K and MAX31855KASA+ to interface it. I could also put some op amp, and connect to Atmega8’s ADC, but 31855 is for lazy people and has everything inside, just connect thermocouple, and get data through SPI interface. It has also some nice features, like error detect (if therm. is damaged or shorted to VCC or GND), it’s not so cheap from the other side.

ATmega8 Thermocouple Thermostat – [Link]

 

Starling – WiFi enabled LED Display

starling

Starling is a modular, Open Source LED display with WiFi connectivity. It comes with a mobile app for easy configuration and usage and has hardware support for Bluetooth.

The LED matrix is driven by an Atmega8 microcontroller (MCU), instead of a standard ASIC. This provides a lot of flexibility in the firmware. The firmware detects and assigns IDs to newly plugged-in modules. The microcontroller also stores font tables; hence if ASCII is sent on the serial (UART) port of the MCU, ASCII is what will be displayed on the matrix. Since the firmware detects adjacent displays, it can easily decide if it needs to display static or scrolling text.

Starling – WiFi enabled LED Display – [Link]

3A Variable Bench PSU with Color Display

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by SHARANYADAS @ instructables.com:

I am playing with electronics since i was a child and made numerous circuits.But still now,i didn’t made any power supply unit for general purpose use.So tired of making PSU for each circuit,I decided to make a stable Bench PSU for general purpose use with some enhanced features.I decided to made the core power supply analog controlled and extra features digitally controlled. So that’s why i choose LM350 linear regulator chip as the heart because 3A is sufficient for day to day use.

3A Variable Bench PSU with Color Display – [Link]

Atmega8 Development Board

ATMEGA8L

Atmega8 Development Board provides a very simple and cost effective platform for prototyping solution.  The compact design provides connection to all the pins of the microcontroller for the user.

  • Prototyping solution available for 28-pin ATmega series AVR microcontroller from ATMEL
  • All the three ports available to the user via standard 10 pin box header with supply of 5 VDC for interfacing circuits
  • Onboard reset switch for easy reset of the microcontroller
  • ISP (In circuit Serial Programming) connector available for chips with ISP support
  • 8 MHz crystal on board
  • UART level shifter circuit using MAX232 IC, on board for easy connection of the board to the RS232 devices

Atmega8 Development Board – [Link]