Pure C Arduino

It's time to do something useful with our small 8-bit computer. Music box is a fun and easy project. It's not demanding from the hardware point of view but it can be a little bit tricky from the software point of view itself - ideal project to learn a lot and not to spend the whole day soldering. What we will need:  an Arduino (of course)  Piezo buzzer  ... and that's all. Now a couple of words of what we want to achieve.  Requirements  Let's point them out: play monophonic melodies by generating tones (1 channel MIDI instrument) the notes will be send by the PC through the serial port  our musicbox should be visible to the PC as a MIDI port  be able to use MIDI player of choice on PC to play MIDI files on our musicbox  The requirements are specified. Unlike most of the simple projects around which play the same melody everytime, which most of the times is hardcoded in the program memory and in order to change it...

A word of warning, this post will be kind of long. I will try to cover the binary communication over serial port basics in 2 languages (C & perl), but I hope every one will bare with me until the end. I'm almost ready to go into some of my "real" projects. In order to do that all that needs to be done is to talk a little about SLIP protocol. SLIP protocol is used to synchronize data between receiver and transmitter on a serial line (not only RS232 , ethernet as well and many other mediums). SLIP is one of the most commonly used option, the other one is Modbus RTU , which describes some timing constraints and requirements during the data transfer. I haven't tried Modbus RTU yet, since SLIP is doing pretty good job for me.  First of all why do we need to synchronize the data at all and what does it mean in details in the first place ? The reason for that is simple (maybe not so obvious in the first place). Consider the following situations: We want ...

Previously I presented a basic way of using timers in order to generate delays. At this time, we'll learn how to use timers and piezo buzzer to generate tones (beeps). The code for that won't be very different from what we were doing previously. Let's start with defining the requirements of our implementation. Our "beeper" function should allow us to generate a beep of given frequency and duration. Simple as that. Just to quickly summarize, when using timer for delay purposes we configured it in CTC mode and configured the prescaler and OCRXA register value so the timer "overflowed" with a 1 kHz frequency (1 ms period), the delay duration was specified by the number of "overflows". Previously, as long as counting the 1 ms cycles was good enough to determine the duration, now the duration depends on both parameters, the actual duration specified as an input parameter as well as the frequency itself.  Let's list steps that our "be...

As long as blinking a led is a fairly simple task. Arduino Library is very handy and can really improve the speed of development of a new projects, making your idea real & tangible. Something similar in C would be useful. At this moment one may ask - why to create a new library, when there are already plenty of those available and ready to use ? Well, thinking like that, we may ask ourselves straight away why to even bother and play with an 8-bit machine when there is so powerful and cheap stuff available out there at the moment everywhere nearly ? The answers for both are short and straight forward: Because we can and it's fun Because we want to learn something Because we want to create some real, useful stuff Another reason to create a library is to have some basic tool set which will be absolutely essential in most of any further developments. First thing which will need in this tool set is a proper (by proper I mean - timer/interrupt based) delay function. I hav...