Which actually looks remarkably familiar - this is almost the same as the uart_puts() I wrote above, except that it handles the possibility of the putchar() function returning non 0 (except in my implementation this will never happen as the characters are always reported as sent OK). Thanks.Īnyway the redirection through a stream is obviously going to add an "extra layer". I'd seen that the thread is old but I hoped that someone else would reply to my doubt. I mean, how are these two approaches (using printf function with the uartstream or just read and write onto UART Control Registers) are going to be compiled? Is the assembly file generated by one more efficent than the other?
I'm always reminded of the German colonel (played by the excellent Gert Frobe) in "Those Magnificent Men in their Flying Machines" trying to operate the plane while reading the manual!
#How to write c code for uart manual
It's kind of unwise to try using a (complex) product like avr-gcc/libc without reading the manual first. PS as Lee says the use of the three different libraries for printf support (and scanf support) IS covered in the user manual. Then in "Custom options" move the highlight down to "" and in the edit box enter "-Wl,-u,vfprintf" then press the button. In the Project Configuration Options go to the library section and make sure both libm.a and libprintf_flt.a are copied from the left to the right pane. If you use Studio it's actually a bit trickier. The Mfile template also arranges for -lm to be used on the LDFLAGs so you will be linking with the libm.a that is needed for accurate (tight, fast) float support. You put a '#' on that first of the three options and take the '#' off the third. # If this is left blank, then it will use the Standard printf version.
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