In message 468AA145.8090404@smiths-aerospace.com you wrote:
One technique I've used in the past that has worked well is to output successive characters at critical points in the code. (It became known around here as "alphabet soup.") If the board stopped spitting out characters prematurely, you have a clue what is wrong.
This is definitely useful for debugging. We often do similar things; like ust writing characters or a counter to some static memory location for post mortem analysis with a debugger.
MPC8260 Clock Configuration
- Bus-to-Core Mult 4.5x, VCO Div 2, 60x Bus Freq 22-65 , Core Freq
100-300
- dfbrg 0, corecnf 0x17, busdf 5, cpmdf 1, plldf 0, pllmf 5
- vco_out 597196800, scc_clk 149299200, brg_clk 149299200
- cpu_clk 447897600, cpm_clk 298598400, bus_clk 99532800
- pci_clk 49766400
One or two of these may be useful, but even that is debatable.
I consider it very useful. We had several cases where customers reported on strange problems, and by just checking the printed data we wre able to see that they either used a wrong board configuration for U-Boot, or that the syctem clock was off, or ...
- Some of these, if wrong, will cause complete board failure and the above won't be printed anyway.
- Most can be deferred till after RAM reloc
No, it cannot, because then you might never see these messages at all.
CPU: MPC8280 (HiP7 Rev 14, Mask 1.0 1K49M) at 447.897 MHz Board: Innovative Systems AP2, CPU1 Build: $SvnTreeRevision: 89 $
Defer till after RAM reloc
NO! Please, please DON'T!
Best regards,
Wolfgang Denk