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MityDSP-L138F Failure to Boot

Added by Wade Calcutt over 9 years ago

I'm trying to get a MityDSP-L138F SOM to boot on a custom baseboard. The SOM powers on; i.e. the Power Good LED lights up, but the boot process goes no further. No data comes out the console UART and the FPGA done LED never lights. I've verified that the module will boot when installed on the industrial I/O board so the issue is definitely with the baseboard. I've assumed the problem is the processor is not able to load the u-Boot executable from flash or that u-Boot (built for the industrial I/O board) is encountering/introducing problems when it programs the functionality of the processor pins. For instance, the baseboard has re-purposed the pins for GP0[x], the Ethernet pins, et al. so conflicts with the custom baseboard may be causing boot failure. Can you verify if this is a valid assumption? Also, do you have any suggestions on what I can try to troubleshoot why the SOM is not booting?

Thanks.


Replies (5)

RE: MityDSP-L138F Failure to Boot - Added by Michael Williamson over 9 years ago

Hi Wade,

Would you be willing to send me a schematic (offline, of course) of your baseboard to review?

Your baseboard could be the culprit as you suspect. You should be able to get at least to a u-Boot prompt without much worry as long as the I2C0 lines and the SPI1 data, address, and chip select pins are not in contention and you are using the console UART for display. Also, you might want to check that your reset line is not asserted, etc.

The I2C bus is used to read the factory configuration data to configure the DDR RAM. The SPI is used to load the first stage and second stage (u-Boot) bootloaders.

Most other peripherals are ignored until u-Boot comes up, and u-Boot does not enable interrupts. So there aren't a whole lot of lines that could be causing problems.

-Mike

RE: MityDSP-L138F Failure to Boot - Added by Wade Calcutt over 9 years ago

Mike,

The SPI1 lines are not attached on the baseboard so that shouldn't be the issue and the reset line is being de-asserted. Hence, that leaves the I2C0 bus, which has a number of devices attached on the baseboard. I will try isolating them and see how that affects the boot. If that doesn't resolve the problem I'll send you a schematic and we'll troubleshoot from that.

Thanks for your quick response.

Wade

RE: MityDSP-L138F Failure to Boot - Added by Wade Calcutt over 9 years ago

Mike,

I isolated the I2C0 bus from the baseboard and I am still having the issue. How should I contact you to forward the schematic?

Thanks,
Wade

RE: MityDSP-L138F Failure to Boot - Added by Emmett Bradford about 9 years ago

Mike -

This is the same issue I am having on the 1808F board.
It boots reliably on your carrier, but not mine.
I thought it was the socket and had it solved, but the issue persists.

I do have a device on I2C0 at address 0x2E.
Are the I2C0 addresses already claimed on the MityARM-1808F as described the Carrier Board design Guide?

I also have a DAC on SPI1_CS1, but it has no MISO.
There shouldn't be a conflict w/ SPI1_CS0 - right?

Document: MityDSP-L138F, MityARM-1808F, and MityDSP-6748F Carrier Board Design Guide
Revision: 1.2
Date: November 11, 2011

3.3.7 SPI Ports
All modules include support for up to 2 SPI ports each having up to 8 chip selects directly controlled by the
peripheral and may also use general GPIO pins as chip select pins if necessary. SPI1 chip select 0, however, is
reserved in order to support booting from the on-board NOR flash. After bootloading, access to the NOR flash is
typically not required, and the SPI port may be used with other chip selects if required. The SPI ports share pins
with other peripherals on the SOC processor. Refer to the SOC datasheet for more details.

3.3.8 I2C Ports
All modules include support for up to 2 Inter-Integrated Circuit (I2C) ports. I2C0 is connected to an on-board
prom (address 1010XXXb) that is used to hold factory configuration data (serial number, MAC address, etc.) and
is therefore dedicated to this function. I2C0 is also connected to an on-board Power Management Integrated
Circuit (PMIC), the TPS65023 (address 1001000b). Users may use the I2C0 port however, to interface to other
devices having different addresses than those mentioned on this bus. The I2C ports share pins with other
peripherals on the SOC processor. Refer to the SOC datasheet for more details.

Thanks,
Emmett

RE: MityDSP-L138F Failure to Boot - Added by Michael Williamson about 9 years ago

Hi Emmett,

I think Wade has resolved his issue offline (there was a design issue on his baseboard that is now corrected).

You're take on the description above is correct. As long as the SPI1 data and clock lines are not in contention and you avoid the I2C addresses on your host board you should be able to boot. If the issue is with the I2C lines you should still get some boot text.

Do you get anything on the console UART when you try to boot or just crickets?

Is this only on power up? Can you push reset and get the unit to boot, or does asserting reset not help?

-Mike

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