some progress

Jarielle Catbagan jcatbagan93 at
Wed Jul 1 04:52:24 UTC 2015


This is great progress!  Since the time you gave me the diff that
updates the files up until now, I was mostly walking through what you
had updated and was working on mostly UART-specific stuff in cpuio.c.

On Tue, Jun 30, 2015 at 8:55 PM, Ed Sutter <edsutterjr at> wrote:
> Jarielle,
> I made some progress regarding boot from sd...
> I took a step back and decided to get the LEDs initialized.
> Doing that allows me to work with a simpler device to verify startup.
> Anyway, I managed to get the GPIO pins initialized correctly so
> that I could control the LEDs.  Then I built a SD card with the
> proper prefixes etc.. in there and was able to boot up the led
> pattern as expected.
> That tells me that it boots correctly, but is not initializing the UART
> as it should. On the other hand, since our UART-boot does work, we can
> at least say that the code in cpuio.c currently is NOT breaking the
> uart initialization that the rom-bootloader does for us.  So, my hunch

I would say so as well.

> is that some clock that drives the UART is not being turned on in our
> code (but it is turned on when the bootloader is forced to boot through
> the UART).
> Anyway, that's my state at the moment.  Done for the night.
> The one tricky part that I'm glad to have out of the way is the prefix
> needed at the base of the image.  That wasn't obvious to me.
> Ed

Now I am going to try to replicate your approach when trying to get
UART to work.

I am the one who needs to catch up to you now. :-)

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