I'm learning for the code in \Keil\ARM\Examples\Measure, I can input/output debug information though ITM and Debug(printf) Viewer normally. When I review the source code, I found a input char is saved into ITM_RxBuffer automatically. Either I change the variable name "ITM_RxBuffer" or I change the magic number ITM_RXBUFFER_EMPTY value(from 0x5AA55AA5 to any other value), it cannot work normally. Why? If KEIL tool-chain do something implicitly?
Great thanks for any response.
Well the debugger recognizes the symbol, and writes over the content in the background via the SWD interface, and your code on the target spins waiting for it to change.