So I finally was able to blow the OTP fuses to have it boot from an MBR based SD card which was good, but then every time I try to boot using either u-boot images or even bootlets from freescale, Bootlets compiled using this. I get in my serial console "HTLLC" repeating which from what I understand is the ROM doing the following.
- H - Header found
- T - Tag found
- L - Load
- L - Load
- C - Call
This is what my efforts have looked like:
▒▒▒▒▒▒▒▒ϱ▒[▒@ ▒ ▒▒▒▒▒J▒@% Data Abort r14_HTLLCHTLLCLCHTLLCHTLLCLC Undefined Instruction r14_unHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCLC Undefined Instruction r14_unHTLLCHTLLCHTLLCHTLLCHTLLC Un▒HTLLCHTLLCLC Undefined Instruction r14_unHTLLCHTLLCHTLLCHTLLCLC Undefined Instruction r14_unHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLCHTLLC
So after googling and reading here, that seems to indicate that there is likely something wrong with memory or power draw issues. To make sure it's not power draw issues, I am not using the MX233's PMU and instead an external regulated power supply to supply the various required voltages (2.5, 3.3, etc). I will not use an external power supply for the power rails as suggested by Igor.
I am using a AS4C32M16D1-5TCN DRAM ic including length tuned traces with a length of ~750 mil, so I am doubtful it's due to signal integrity issues. Based on discussion here, it seems that there has been varying success.
My questions are these (I am using freescale bootlets since they seem recommended here when trying to work out issues):
- What is the first function the ROM calls? Is it _start() in init-max23.c? Basically, what's the C in HTLLC calling?
- Are these first L's loading into external memory, or the internal SRAM?
- How can I change the speed of the default DRAM assumed in the bootlet?
- I see functions like init_mddr_mt46h32m16lf_96Mhz() but if I stick a printf's at the start of each similar function at the beginning I don't see anything different on my terminal. So I assume these aren't used to setup DRAM.
- Am I SOL for going with the Alliance DRAM? I am not seeing any DRAM's used in the omnilex nor the freescale reference design available on digikey or mouser, so it seems this is true sadly.
Note, this is an extension somewhat of my previous post here.
Seems my 2.5v rail is not powering up, even when nothing is connected to it, huh.