Initiating PRU Single-Stepping Using Prudebug?

GoogleGroups
1

I am running an example similar to PRU_PRUtoPRU_Interrupt from TI’s pru support package, and have download and installed prudebug (the suggested alternative from LinuxCNC configs/pru-examples/README appears to require an installation of the complete LinuxCNC project in order to get a “HAL” environment and my eMMC does not have enough remaining space for this). Both PRU0 and PRU1 are started from a C program by the arm. I can insert a HALT statement into PRU1, for example, and then examine registers using prudebug, which is much better than previously. However, single-stepping past the HALT statement does not work (at least I can not get it to work). If I insert a QBA 0 (which in binary from found using DIS is 0x79000000), and re-make, then the program can be put into an infinite loop, and can be stopped using HALT. It was then possible to use the command WRI 0x9 0x79000001 (0x9 is the instruction address and this replaces QBA 0 by QBA 1), and it was then possible to single-step through code from that location on. Although this does seem to work, it is very unwieldy and I am guessing there is a much cleaner method to be able to halt the PRU and initiate single-stepping; do any of the experienced coders in PRU Land have suggestions for a more efficient methodology? Thank you.
Bit_Pusher

2

Did you replace the HALT instruction with a NOP and start the PRU
running again? I _think_ that will work, but I haven't tested it.

If you just want to single step through your code, you can load the code
in the PRU, keep the PRU in reset, then launch the debugger and start
executing/single-stepping at the beginning. I'm not sure if this would
work for you (it depends on what your other C programs are expecting
from the PRU), but it's generally worked well enough for me.

Once your code is running, you can still pause the PRU and examine
registers & memory to see if your code "ran off into the weeds".

3

Hi,

Referring to the pru_remoteproc driver (which is used by the BeagleLogic kernel driver) in a early version tree for BeagleLogic which highlights the process of resuming the PRU - Incrementing PC by 1 (skipping over HALT), then setting CONTROL_ENABLE bit to 1 and soft-resetting the PRU.

Hope it helps

Abhishek