#Codevisionavr xmega io input code
Each shelf has an address in memory, so that the controller knows where to find it the C code manage the variables and pass parameters to the assembly code either by value or by reference. In an 8-bit processor, like the AVR ATMega 16 we are using, the shelf can hold 8 books, where each book is a one bit binary number, a 0 or 1. Registers are like shelves in the bookshelf of processor memory. All information in the microcontroller, from the program memory, the timer information, to the state on any of input or output pins, is stored in registers. If someone could help me out that would be wonderful Where did you get that impression? The section of the AVR FAQ dealing with register usage doesn't say anything about preserving registers in which parameters were passed except in the call saved section where it explicitly says that you must preserve such registers even if parameters were passed in them.ĪVR Registers. I've searched everywhere online, looked inside the AVR header files, and read a book. Long story short, I don't want to use the AVR libraries in my C code I want to access the registers specifically through their addresses using pointers in C. There's a section in the FAQ called What registers are used by the compiler, provided that you installed WinAVR in the default directory you can find it in the here,however it focusses on the interface between ASM en C programs Since this is self-study, it's taken me a while to learn how the things work at the bare metal.