Custom sama5d2 board not booting

Discussion around products based on ARM Cortex-A5 core.

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sanduo
Posts: 7
Joined: Fri Oct 05, 2018 6:30 am

Custom sama5d2 board not booting

Tue May 21, 2019 2:55 am

We have designed custom board using the ATSAMA5D27C-CU, based off the SAMA5D2 Xplained EVL board.

At this stage what I can confirm is the board powers up OK, both clocks are running on the MPU (12MHz and 32K) and the SAM-BA monitor works through USB interface. We have both uSD and eMMC interface (based off Xplained board).  I am currently testing the uSD version.

With a programmed uSD card that is tested and boots on the xplained board, it does not boot on our custom board, the system enters SAM-BA. Probing the pins (CLK of SD interface HC1 PA22 )of the xplained board I can see an output from the MPU, and the system boots
On our board there is no CLK output (PA22) for the HC1 interface and the system enters SAM-BA.

I can confirm the card detect functions correctly into PA30 on our board, same as the xplained board.
Even though we don’t have the eMMC fitted, probing the clk pins also showed no activity, where the xplained board produced an output.

We have been using sam-ba.exe application through the usb interface experimenting with the BUREG settings, but no change helps.
The Fuse reg is default

Does the operation of the SAM-BA indicate the MPU is running correctly?
What would prevent the MPU from configuring the PIO to access the SD?

Any suggestions on debugging this would be much appreciated.
blue_z
Location: USA
Posts: 1924
Joined: Thu Apr 19, 2007 10:15 pm

Re: Custom sama5d2 board not booting

Wed May 22, 2019 6:20 am

sanduo wrote: I can confirm the card detect functions correctly into PA30 on our board, same as the xplained board.
Based on what?

sanduo wrote: Does the operation of the SAM-BA indicate the MPU is running correctly?
Only to the limited extent that one USB port (and whatever it takes to support that) is operational.
IOW only what you test is what you know is operational.

sanduo wrote: What would prevent the MPU from configuring the PIO to access the SD?
That's a presumptuous way to phrase the problem. An outcome that was not achieved does not imply that it was "prevented".
Are you actually probing for signals at the balls of the SoC?
Maybe the configuration was performed, but it was not observed because there's an open circuit?

sanduo wrote: Any suggestions on debugging this would be much appreciated.
You claim clocks are okay, but what about voltages (e.g. VDDSDMMC) and the power-up sequence?

You need to utilize what is functional (i.e. the SAM-BA Monitor) instead of solely focusing on SD card boot as the next step.
The SAM-BA Monitor on the target and a terminal emulation program on the host connected to the DBGU port can examine and modify memory and peripheral registers.
You could try to manually perform the boot procedure described in section 50.9.1.1 of the SoC datasheet.
Or you could load and execute test programs (e.g. diagnostics derived from the Atmel SoftPack examples) using the SAM-BA utility.
Have you tested DRAM yet?

Regards
sanduo
Posts: 7
Joined: Fri Oct 05, 2018 6:30 am

Re: Custom sama5d2 board not booting

Fri May 24, 2019 8:16 am

Thank you;)
We sorted it out, one resistor hold it.

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