måndag 1 oktober 2012
DIY RS232 shield for the Olimex E407
First of all I discovered that the Olimex proto shield doesn't fit the board very well. I had to grind off one of the corners to make it fit with the power supply capacitors on the E407 board. A regular proto shield won't fit better... it seems like the capacitors aren't too well placed on the E407 board :-/
Since I am not very experienced in programming the STM32 processor I had to verify the construction with an AVR I had laying around and it seemed to work fine. I couldn't make it work with the E407 though.
I found out that the source I had downloaded from ST's site is designed for the Discovery board which has an 8 MHz external clock source. The E407 has a 12MHz clock. I had to generate a new system file with ST's excel tool. The patch can be found here.
I then compiled the example from Elias electronics blog, which seemed to work fine.