UART1 pin conflict, when using LCD and CAN capes

[William]

Hello,

The scope of my project is to get CAN messages from CAN bus and display some information on an LCD.

The HW components used:

- BeagleBone Black

- CAN cape https://www.waveshare.com/rs485-can-cape.htm

- LCD cape gen4-4DCAPE-43T http://www.4dsystems.com.au/product/gen4_4DCAPE/

SW: Debian 9.2 2017-10-10 4GB SD IoT 

I installed bb.org-overlays. 

root@beaglebone:~# cat /sys/devices/platform/bone_capemgr/slots
 0: P---L-   0 4D 4.3 LCD CAPE - 4DCAPE-43T,00A1,4D Systems,BB-BONE-4D4R-01
 1: PF----  -1
 2: PF----  -1
 3: PF----  -1

When I try to enable the CAN cape:

echo BB-CAN1 > /sys/devices/platform/bone_capemgr/slots
-bash: echo: write error: File exists

I also tried to enable the cape from uEnv.txt file:

cape_enable=bone_capemgr.enable_partno=BB-CAN1
[    3.557591] bone_capemgr bone_capemgr: slot #4: BB-CAN1 conflict P9.26 (#0:BB-BONE-4D4R-01)
[    3.566124] bone_capemgr bone_capemgr: slot #4: Failed verification
[    3.586720] bone_capemgr bone_capemgr: loader: failed to load slot-4 BB-CAN1:00A0 (prio 0)

In BB-BONE-4D4R-01-00A1.dts device tree source file, pin P9.26 on BBB UART1_RX is used by LCD cape.

So far, I am able to use one cape at a time.

How can I change the device tree files in order to be able to use both capes simultaniously?

Since CAN cape provide a UART selection, can other UART be configured as CAN interface?

Being in this stuck point for some time, any idea is very appreciated. Thank you.

[Robert Nelson]

P9.26 is the touchscreen interrupt pin. So if you don't mind losing that feature of the LCD.

Regards,

[William]

Thank you, 

Can I change the pin map for P9.26 to use another pin? Or maybe change the CAN interface to another UART?

[Robert Nelson]

On Thu, Oct 26, 2017 at 7:13 AM, William <pana...@gmail.com> wrote:
> Thank you,
> Can I change the pin map for P9.26 to use another pin? Or maybe change the
> CAN interface to another UART?

Sure, just spin an adapter PCB board and move it, it only has to be
one layer, so it'll be cheap..

Regards,


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

[William]

Ok, but I guess I will have the same conflict with device tree files.

I tried to modify the dts file for CAN1 to use CAN0 interface (pins 9.19, 9.20).

Then I compiled the file and copied to /lib/firmware

dtc -O dtb -o BB-CAN1-00A1.dtbo -b 0 -@ BB-CAN1-00A1.dts

I updated the init image with

update-initramfs -uk 4.4.91-ti-r133

I also tried to enable from /boot/uEnv.txt:

cape_enable=bone_capemgr.enable_partno=BB-CAN1

Can you please tell me what I am doing wrong?