EP9302 Boot problem

Development Boards MicroMod
1

Hi,

Hope that i m in the right place, even if i had made a mistake on where i have to publish my request i hope that you help me in my problem.

I have designed a custom board based around EP9302 the same as the cirrus logic evaluation board EDB9302A but only missing usb slave and audio and power supply where i use some LM317 with high current transistor.

When i power on the board the LED flushes means that the mcu is alive.

I had used the utility download.exe to download redboot.bin that come with in the package linux_1-0-3-9302a.tar that i had got from arm.cirrus.com website.

By pressing reset and boot from srial button the download process is fine and the download utility upload the first boot stage and then download the redboot.bin.

After downloading redboot every things looks fine as redboot identify the flash and sram manufacturer.

When every thing is done i press the reset button to reset the board and boot the redboot image.

After resetting the board the MCU became in short circuit ( about 1 ohm of load impedance). I had got the same problem for 5 boards with different MCU newly purchased. I dont know what is the problem exactly.

So my question is :

  • Have some one got the same problem before ?

  • Have some one any idea about the problem ?

  • Have i missed some thing to do ??

  • Do redboot can harm the MCU if it is not configured correctly in compiling time ?

  • Do i need to compile my own redboot binary file to solve the problem ?

Please help me this problem drive me crazy.

Thanks.

2

Someone here might have an idea but I’d say your odds are not too good. I was going to suggest you try Technologic Systems - but I see you already have.

I am curious about where you measure the short. One of the supply pins?

You didn’t connect the (unused) USB slave pins to ground by any chance? If redboot tried to enable those…

Your best approach might be to get a JTAG adapter and exercise the pins “by hand”. That would really be tedious though…

3

Thanks for your reply , yes i had forgot to explain that the short is between all VCC (3.3v) and GND and (Vcore 1.8V). This shorts are measured on ep9302 leads after dissoldering it ic from the board.

I had tried use a board with only MCU, reset circuit, power supply , SRAM and flash and the result was the same. I can download but after reset i got an IC with short circuite between VCC Vcore and GND.

Please Can some one provide assistance for this problem.