2009-02-26 16:31:15     Problem booting over UART on BF548 EZKIT

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2009-02-26 16:31:15     Problem booting over UART on BF548 EZKIT

Ross Butterworth (UNITED STATES)

Message: 70038   


The Problem:


I'm trying to boot my BF548 EZKIT over UART and ldr-utils keeps timing out on "Trying to read autobaud".




Background Info:


After I initially set up my host, I tried to boot with U-Boot over UART to make sure everything was set up correctly, and was successful.  I got some unprintable charachters back that I did not expect, but did eventually get to the "bfin>" prompt.  So I figured everything was all set, and went to get some dinner, and when I got back I could not reproduce my success.  Now I just time out on the "Trying to read autobaud" step.




I went through the Troubleshooting section of [http://docs.blackfin.uclinux.org/doku.php?id=bootloaders:u-boot:loading#troubleshooting] and can eliminate every item on the list as not being my problem.  I know I am specifying the correct device on my host, since there is only one serial port in my host.  I'm sure there are no other terminal programs open.  I'm sure i'm connecting to the correct UART, since there is only one I can connect to.  The bootmode is specified by switch SW1, position 7 for UART boot, and the UART is enabled by SW7.  These switches have been tripple chcked.  The number of times I press reset before booting has no effect.  My serial cable is fine, since I can use it to connect to other hardware.  I'm not using any kind of USB adapter.  The "low level test" also fails.




This issue is particularly irksome because I did get the EZKIT to boot successfully the first time.  I can't think of anything I could have done that would have trashed my board.




Has anyone encountered this problem before, and if so found a solution?  Any insight at all would be helpful.








2009-02-26 16:45:33     Re: Problem booting over UART on BF548 EZKIT

Mike Frysinger (UNITED STATES)

Message: 70039   


the low level test described on that page is how you should test things.  in other words, open up a terminal connected to your board and hit space.  if you dont get back anything, check the misc hardware settings, reset the board a few times (power cycle even), and then type a few random chars into the terminal again.


in other words, you dont need to muck with your software setup while trying different hardware things.  if the board doesnt respond with a few bytes, then that largely points at hardware config being incorrect.


you can check the switch settings on the bf548-ezkit page:



to keep things simple, you'll probably want to disable CTS/RTS on the UART ...




2009-02-26 19:38:21     Thanks for the quick reply

Ross Butterworth (UNITED STATES)

Message: 70053   


Looks like everything is working normally now.  Seems like the problem was something silly.  I was probably setting SW1 wrong.  SW1 is a rotary 16 position switch with a notch on the top of it that determines the boot mode.  It's not really clear which way the switch is pointing.  There is a little dot on one side of the notch, so I assumed that was the direction the switch was pointing.  The board would boot from Parallel Flash when I had the switch pointed at position 1, as it should.  When I rotated the switch 180 degress to position "9" it would also boot from parallel flash.  Boot mode 9 is "reserved" according to the manual, so I don't know exactly what it does.  This lead me to think that I might have the switch set totally wrong.


Turns out that was the problem.




2009-02-26 19:42:09     Re: Thanks for the quick reply

Mike Frysinger (UNITED STATES)

Message: 70054   


there should be a notch on the side as well to indicate which side it is "pointing" at ...


usually i just click once, hit reset, and see what comes out of the serial.  if i see nothing, i repeat again until i do see something ;).