UART1 pin conflict, when using LCD and CAN capes


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

The HW components used:

SW: Debian 9.2 2017-10-10 4GB SD IoT

I installed

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.

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


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

joi, 26 octombrie 2017, 14:37:51 UTC+3, RobertCNelson a scris:

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


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:


Can you please tell me what I am doing wrong?

joi, 26 octombrie 2017, 15:20:42 UTC+3, RobertCNelson a scris: