Execute own software on the OMAP

[Go4IT]

One of my favorite goals would be to bring some own software to run on the mainboard (the OMAP-processor). I think about some really simple things as a proof-of-concept in the first, like "blinking a LED" or just see level swap on an DSO. And if this works, go ahead with something like writing chars to an UART and receive them by an terminal application on the PC.
A milestone would be to bring an U-Boot bootloader to run on the board, which where the first step to install a Linux on it

We have all the tools to do this, all it need's is knowledge to write a software and get it onto the device and execute it. One possibility would be to use the internal SRAM of the OMAP, like the J-Flash tool uses for it's RAMcode part. Another way could be to flash it somewhere, e.g. an unused area of the mainboard-flash, so it does not interfere whith other parts of the unit.

On both ways, to get it to run, we need to stop the CPU, set the program counter (PC) to start address of our program and start the CPU again. In Segger J-Link to halt the CPU simply type "halt" command into the J-Link Commander CLI. It then stops execution and also writes the current contents of all registers:

omap5948_halt_cpu.png

As you see the PC is somewhere different. To bring it to the start of our application, just do "setpc <ADDR>". This will load the PC register with the value we need. To start executing it, just resume execution by issuing the "go" command.

Now, who is willing or able to provide a piece of software to send some chars to an UART or let some GPIO-Ports "blink" ?