AM3352: Am3352 cannot be started from SD card

Hello Willson,

I am assigning this to a hardware engineer to comment on your interface question. Meanwhile, please give us more details about 2) and 3).

2)
What do you mean by "core board"?
What do you mean by "the initial program in SD card"?
What operating system are you trying to boot into?

3) Please rewrite this. I am not sure what you are saying here.

Regards,

Nick

Are you saying, you purchased a board to get started and the SD card which came with that board is being used to boot a different board design that has different connections?  If so, please provide details of all differences. The SD card SDCD signal connection difference you mentioned above is one example.

The AM335x Technical Reference Manual (TRM) has a Booting section in the Initialization chapter which describes details of the device boot procedure. You can refer to this document for more information which may be helpful when debugging your boot problem.

For example, the TRM describes how the card detect signal is not used by the device boot code to determine when a card is inserted. I'm not familiar with the details, but assume the boot code detects a card is inserted by performing a read operation and looking for a response. Therefore, I would not suspect the SDCD signal connectivity difference to be what is preventing the device from booting from SD card.

If you have other hardware differences, the SD card image may not be compatible with your hardware platform. If this is the case, your system may be getting hung further into the boot process. I will not be able to help with any software related questions, but can answer specific questions related to the MMC0 signals and connectivity to the SD Card. 

Regards,
Paul

Hello   Nick  , Paul 

1, The purchased core board refers to a board purchased from another manufacturer, including power supply, CPU, NAND, DDR3, and then the core board is connected to the bottom board through a connector to form a hardware device. Now the program in the SD card is provided by the core board manufacturer. After installing their core board on the bottom board, it can be started normally from the SD card.
Later, we made the core board by ourselves, referring to the purchased core board, the pin definition was the same, and then using the same base board, the same SD card, in the case of the same BOOT configuration, the serial port will print ccc normally after power on, but after inserting the SD card, the serial port stops printing CCC, and then serial port Nothing happens. I measured the CLK and CMD signals with an oscilloscope, and found that there was only a waveform at the moment when the SD card was inserted. After consulting the above-mentioned core board manufacturers, they replied that the clock signal can only be available when there is data transmission between the SD card and the CPU.
To explain again, the core board we made by ourselves has the same pin definition as the core board purchased，PIN to PIN. The difference in hardware design is that the above-mentioned manufacturers use discrete power supplies. We use TPS65910A3A1RSL. The power and clock of the CPU on our core board are normal.

2, Now we want to know what is the process of booting from the SD card after eliminating the hardware problem

3, Which files are needed when we choose to boot from the SD card. We now suspect that the initialization program provided to us by the core board supplier is incomplete.

Thank you for your help

There must be some significant difference between the two core board designs. You will need to focus on every small detail to find what is causing the problem. It could be as simple as your PCB design has too much loop inductance in decoupling capacitor connections which allows the supply rails to have too much noise. This is just one of many examples of small details that can effect system performance. You may need to connect a debugger that allows you to step through code execution to determine how far boot proceeds before encountering the problem. Finding where the system boot failure occurs could be very helpful in understand what is causing the problem.

Regards,
Paul