On Fri, Feb 5, 2016 at 5:55 PM, Brian Anderson <[email protected]> wrote:
> I have a sensor hooked up to UART1.  This seems to work just fine using
> cape-universal and config-pin to setup P9-24 and P9-26 in uart mode.
>
> When I modify uEnv.txt to use BB-UART1 overlay, I am unable to read data
> from the sensor.
>
> Relevant portions of uEnv.txt looks like this:
>
> # Don't enable cape-universal
> cmdline=coherent_pool=1M quiet
>
> # Enable UART1 and I2C1 overlays
> cape_enable=bone_capemgr.enable_partno=BB-I2C1,BB-UART1
>
> And I have commented out the original cmdline:
>
> #cmdline=coherent_pool=1M quiet cape_universal=enable
>
> Slots look like this:
>
>  0: PF----  -1
>  1: PF----  -1
>  2: PF----  -1
>  3: PF----  -1
>  4: P-O-L-   0 Override Board Name,00A0,Override Manuf,BB-I2C1
>  5: P-O-L-   1 Override Board Name,00A0,Override Manuf,BB-UART1
>
> Kernel and rootfs:
>
> debian@bbb2:~$ uname -r
> 4.1.16-ti-rt-r44
> debian@bbb2:~$ cat /etc/dogtag
> BeagleBoard.org Debian Image 2016-01-17
>
> I have also pulled the latest bb.org-overlays and run install.sh.
>
> I have this working on another system with 4.1.13-ti-r35 with the 2015-11-09
> rootfs.  If I am correct in analyzing the BB-UART1 dtb that is working on
> this system, it appears as if P9_24 is configured with a pulldown resistor
> and P9_26 is configured with a pullup resistor.  The BB-UART1 dtb on the
> system where this is not work (and the current version from bb.org-overlays)
> has no pullup/pulldown resistors configured for those pins.  Looking at
> cape-universal (that works), it appears as if P9_24 and P9_26 are both
> configured with pullups.
>
> So, I'm assuming that this is why my current BB-UART1 setup is not working.
>
> Is the configuration of the current BB-UART1 (actually all of them) without
> pullup/pulldown for UART mode by design?  If so, why?  And of course, the
> converse question for cape-universal.
>
> Not being a H/W guy, maybe someone can inform me as to why my current
> BB-UART1 doesn't work and why these dtb's are thusly configured.

Sorry, just fixed this today, my edma fix for spi/mcasp, broke usart1/2..

cd /opt/scripts/tools/
git pull
sudo ./update_kernel.sh --ti-rt-channel --lts-4_1

BB-UART1 & BB-UART2 will work again...

Regards,

-- 
Robert Nelson
https://rcn-ee.com/

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