AM5716: PCB does not respond to UART3

ZaiHang,

A few questions and experiments that will make this debug smoother.

1. Is this an existing working platform you re-designed the PCB for? 

2. When compared to the AM571x EVM schematics, what did you change and what were optimized?

3. Do you have UART parameters set for 115.2 Kbps, 8 bits, even parity, 1 stop-bit, no flow control?

4. Based on the datasheet, ROM expects the UART3 pinmux'd on UART2_CTSN/RTSN, is this how the signals are routed?

3. Probe the signal lines and checke if there are any toggling, or if the proper commands are going through.

4. Connect to JTAG and dump the PC register, as well as the tracing vectors (0x4037 F040, 0x4037 F044, 0x4037 F048, 0x4037 F04C)

Yes, the schematic will be helpful if these debug steps do not resolve the issues.

Best Regards,

Shiou Mei

0647.AM571X_REV1_1A.pdfHi, Shiou Mei,

Thanks for quick response.

The target board is not working yet. Below are the answers to the questions.

. Is this an existing working platform you re-designed the PCB for? 

No, this is the first prototype board.

2. When compared to the AM571x EVM schematics, what did you change and what were optimized?

I have removed unused parts in the design, such as HDMI, LCD, QSPI falsh etc.

The board is intend to work from eMMC and first time boot-up shall through SDCARD or UART.

3. Do you have UART parameters set for 115.2 Kbps, 8 bits, even parity, 1 stop-bit, no flow control?

Yes. But there is no response at all.

4. Based on the datasheet, ROM expects the UART3 pinmux'd on UART2_CTSN/RTSN, is this how the signals are routed?

Yes, Pin C28 and D27 are used according to EVM design.

3. Probe the signal lines and checke if there are any toggling, or if the proper commands are going through.

There is toggling of signals on UART3_RXD (from external), but there is no local transmission toggling on UART3_TXD.

4. Connect to JTAG and dump the PC register, as well as the tracing vectors (0x4037 F040, 0x4037 F044, 0x4037 F048, 0x4037 F04C)

Unfortunately, there is no JTAG lead-out to teh PCB, we are trying to jump wire for testing.

Here atatched the schematic PDF file for review.

Thanks & Regards,CPU Main Board.pdf

Hi Shiou Mei,

Thank you for your reply.

First question: We have done he boot up test in 2 option:

1.UART:

The issue is that when the device is boot up, we will continuously receive a message" JEJEJEJE..." from the HyperTerminal. And we get no response when we trying to download the SPL.

Do you have any relevant material that is available for us in order for us to boot from UART?

2.SD card boot up:

We still cannot boot from SD Card mode, also, if there is any relevant document for troubleshooting?

Next question:

On our board, we have already implemented USB port adaptor to JTAG and UART3.

Is there any software and user guide to USE JTAG and UART?

ZaiHang,

What software and revision are you using?  Typically there will be user guide to help you with debug purposes.

As for JTAG, you will need to install CCS, configure a Target Configuration File to connect to AM5716, and then connect to the cores to access the registers.  These links may be helpful:

https://www.youtube.com/watch?v=11lsNYW7zkw

https://software-dl.ti.com/ccs/esd/documents/ccs_debugging_jtag_connectivity_issues.html

Best Regards,

Shiou Mei

Hi,

We are using AM5716 custom design PCB for this test.

The test is done according to "AM57_UART_Boot_SOP_By_TI_Rio_Final.pdf" 

Below U-boot-SPL.bin is generated from ti-processor-sdk-linux-am57xx-evm-06.03.00.106.

7750.u-boot-spl.rar

and we follow the SOP, power up the board to download the SPL. serial port setting at 115200, 8,EVEN,1, no flow control.

Until complete.

Then try to download U-Boot.im from Teraterm using Y modem, (tried with Settings 115200,8 EVEN,1 and 115200,8,N,1). both unsuccessful.

Could you pls help to solve the issue?

Regards,

ZaiHang,

A few more setup questions:

1. Are there only one COM port you can connect to?  I am expecting to see "CCCC" as according to the PDF and not "JE!JE!JE!JE!" like in your setup.  Looks like the serial connection was not configured correctly

2. Can you provide more information in the SD boot fail?

3. Were you able to connect to JTAG and dump the PC and tracing vectors?

4. Please re-attach the schematics; the previous one uploaded was a blank page.

Thanks & Regards,

Shiou Mei

Hi,

Thanks for quick response.

1. Are there only one COM port you can connect to?  I am expecting to see "CCCC" as according to the PDF and not "JE!JE!JE!JE!" like in your setup.  Looks like the serial connection was not configured correctly.

The comport is connected through an on-board FT2232HL to USB, together with the JTAG port, exactly follow the design in AM571x EVM.

I believe it is correct the UART3 shall sent "JE!JE!..." continuously when the board is powered up. 

However, it is wrong when we download U-Boot-SPL.bin into the board through UART3. The correct response shall be "CCC..." when did the same on the EVM IDK. SO what could possibly be wrong? because we saw the SPL downloading is successful from PERL terminal. Shall the SPL code be modified for custom board?

2. Can you provide more information in the SD boot fail?

When we set the board to SD card boot, is SYSBOOT[15:0]=0x1000 0001 0010 0010 correct?

on SD card interface, we can measured the CLK, CMD, D0 having signal toggle while D1, D2,D3 do not have.

3. Were you able to connect to JTAG and dump the PC and tracing vectors?

We have built a Helloworld project to debug the CPU A15 core, it is working.

Could you guide us how to debug the board on U-Boot process? and where to find tracing vectors?

4. Please re-attach the schematics; the previous one uploaded was a blank page

Here is the attachment.

AM571X_REV1_1A_PCB_Sch.pdf

Thanks again.

Regards,

Hi ZaiHang,

ZaiHang Ma said:

The correct response shall be "CCC..." when did the same on the EVM IDK. SO what could possibly be wrong? because we saw the SPL downloading is successful from PERL terminal. Shall the SPL code be modified for custom board?

1) Can you confirm that on the TI IDK you are able to get UART boot functional? Can you get to u-boot prompt with UART boot on TI IDK?
2) Do you have pins same as TI board on your custom board for UART3 pins? Can you confirm that as well?

Best Regards,
Keerthy

Hi,

Below is the reply:

1) Can you confirm that on the TI IDK you are able to get UART boot functional? Can you get to u-boot prompt with UART boot on TI IDK?

Yes, the IDK response "CCC..." and works well.

IS it possible that we need to modify the SPL file for our design since the QSPI is removed from the EVM design?

2) Do you have pins same as TI board on your custom board for UART3 pins? Can you confirm that as well?

Yes, confirm.

Hi,

Can you take a look at: http://software-dl.ti.com/processor-sdk-linux/esd/docs/06_03_00_106/linux/How_to_Guides/Hardware_Setup_with_CCS/TMDXIDK5728_Hardware_Setup.html

This should help you attach to A15 using JTAG(CCS). You can try to boot using MMC and of course you are
not seeing any traces on UART. You can try to attach to A15 and load u-boot-spl.bin to see where it is hanging.

Best Regards,
Keerthy