Pure C Arduino

Clock - I think that it's the most popular idea for a project with the MCU . It's not that hard from both software and hardware side to realize but not that trivial as well, not mentioning the fact that once realized it sits somewhere in the house, constantly reminding about itself and brings a kind of satisfaction :). There are a lot of options really to implement, a buzzer alarm, perhaps a thermometer, display and buttons servicing, perhaps maybe even serial port usage for NTP synchronization. But ... The most challenging thing - like in every clock is the time reference source. There are a couple of options: well calibrated frequency source acting as an interrupt source Real Time Clock module with external crystal ( < 20 ppm ) internal clock These days RTC chips are so cheap and widely available that they are really the only reasonable choice, but if we're only planning to play around a bit with the software without paying much attention to accura...

This post is an addendum to the previous one. To make our lives (as a software developers) even more easier it is possible to recreate a real audio without even having to built the R-2R ladder. Atmega328 comes with a PWM capable timers and they're good enough to produce audio quality analog signal. PWM fundamentals I'm not going to go into details about PWM digital to analog conversion, on this blog I focus on my code and do not intend to cover the theoretical background very thoroughly. Please take some time and familiarize yourself with the PWM theory explained on those sites: Open Music - PWM DAC Open Music - Dual PWM Open Music - Distortion Analysis Open Music - PWM Tutorial In general every PWM DAC can be described by a PWM frequency - f pwm (the frequency of the squarewave generated - which is constant) and the PWM bit resolution - bitres (which describes the granularity with which we can control the duty cycle). All of three Arduino's...

There is a lot of projects out there which use  R-2R ladder and an Arduino to recreate sounds from either SD card or short audio clips programmed directly to MCU's flash memory. Although using SD card is fairly reasonable and provides a lot of flexibility it's not very challenging (from the software point of view) and it requires some additional hardware. Believe it or not we already have all the needed hardware in the Arduino itself. Assumptions In this project I'll play mp3 or any other multimedia files from the PC using Arduino. Bellow are the details: Play PCM 8kHz 8bit Audio with Arduino Audio samples will be transfered via USART from the PC in binary format using SLIP Audio files will be decoded on the PC side and only the RAW data will be send to Arduino Timing Arduino is a powerful machine, powerful enough that it's possible to play audio with even higher sampling rates and bit-resolutions than assumed above, the bottleneck in this...