I wrote a piece of assembly code to use a button on my CORTEX-M4F board and went into Debug mode. When I ran the code the whole thing crashed, some error messages came up which I had never seen before and since then Keil hasn't been able to find my board and every time I try to run a program it says: "no target connected", "flash download fail".
Don't know what to do.
I'm afraid you have modified pins for JTAG in your short application. And after that the JTAG pin(s) will be always locked to alternative functions.
Check TI's websites for unlocking JTAG pins of LM4F.
I actually have a STM32F047VG board, do I still have to go on the TI website or ST's?
Eh... Of course ST's.
If you go to TI and ask about STM32F4xx, they'll smash you into pieces.