On 8/24/2017 3:51 PM, mugginsac wrote:
> OK that made some progress. It still looks like some command processor is 
> running at the same time as the login process.
> 
> It printed "U-Boot SPL 2017.05-dirty (Aug 23 2017 - 15:20:51)
> drivers/ddr/alt" on the serial console and then went quiet. Next thing I 
> saw was that it had apparently loaded the kernel and was waiting for a user 
> name.
> 
> However, some process was feeding characters that were being consumed by 
> the login process. Every so often it would hit something that corresponded 
> to something the command processor recognized and display a bunch of stuff 
> on the screen again, like a help menu. Look at the file I captured and see 
> if it helps understand what is going on. I don't know what process is 
> putting up the various help menus.

It almost sounds like you've got some sort of serial echo going on,
but typically the echo setting is opposite of what you're seeing (ie:
if echo is on, the putty/minicom Tx characters are echoed back to the
putty/minicom screen, you're seeing what might be DE10 Tx data echoed
back to the DE10 Rx).

My DE10 certainly doesn't behave the way you're describing.  I wonder
if there could possibly be a short between the UART Tx and Rx lines on
the DE10?

Do you have a 'scope to check the physical Rx/Tx lines?  If not, you
may be able to use the RXD/TXD LEDs (next to the UART USB connector)
to diagnose.  You should only see the RXD light if you actually type
something into the terminal window.  If you see RXD along with TXD
without typing anything, that's your problem...then you just need to
figure out why it's happening.

Note that the LEDs are driven by the FTDI USB chip and don't directly
indicate the presence of traffic on the physical UART Rx/Tx lines to
the SoC.  So just because you don't see the RXD LED turn on doesn't
mean that the Rx/Tx lines couldn't be shorted.  You'd need to probe
the HPS_UART_RX line (pin 30 on the U12 FTDI chip) with a 'scope to be
sure what's going on.

What happens if you try to boot with the uSD image that shipped with
the DE10 while you have the USB UART connected?

-- 
Charles Steinkuehler
[email protected]

-- 
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
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