UART-4 not transmitting (BB Green)

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Here is my BB info:

`

root@beaglebone:~# uname -a && cat /sys/devices/platform/bone_capemgr/slots

Linux beaglebone 4.1.15-ti-rt-r43 #1 SMP PREEMPT RT Thu Jan 21 20:13:58 UTC 2016 armv7l GNU/Linux

0: PF---- -1

1: PF---- -1

2: PF---- -1

3: PF---- -1

5: P-O-L- 0 Override Board Name,00A0,Override Manuf,BB-UART4

root@beaglebone:~/pyy# cat /boot/uEnv.txt

#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0

uname_r=4.1.15-ti-rt-r43

##uuid=

#dtb=

##BeagleBone Black/Green dtb’s for v4.1.x (BeagleBone White just works…)

##BeagleBone Black: HDMI (Audio/Video) disabled:

dtb=am335x-boneblack-emmc-overlay.dtb

##BeagleBone Black: eMMC disabled:

#dtb=am335x-boneblack-hdmi-overlay.dtb

##BeagleBone Black: HDMI Audio/eMMC disabled:

#dtb=am335x-boneblack-nhdmi-overlay.dtb

##BeagleBone Black: HDMI (Audio/Video)/eMMC disabled:

#dtb=am335x-boneblack-overlay.dtb

##BeagleBone Black: wl1835

#dtb=am335x-boneblack-wl1835mod.dtb

##BeagleBone Green: eMMC disabled

#dtb=am335x-bonegreen-overlay.dtb

cmdline=coherent_pool=1M quiet cape_universal=enable

#In the event of edid real failures, uncomment this next line:

#cmdline=coherent_pool=1M quiet cape_universal=enable video=HDMI-A-1:1024x768@60e

##Example v3.8.x

#cape_disable=capemgr.disable_partno=

#cape_enable=capemgr.enable_partno=

##Example v4.1.x

#cape_disable=bone_capemgr.disable_partno=

#cape_enable=bone_capemgr.enable_partno=

#capemgr.enable_partno=BB-DCAN1,BB-UART2

cape_enable=bone_capemgr.enable_partno=BB-DCAN1,BB-UART4

##Disable HDMI/eMMC (v3.8.x)

#cape_disable=capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN,BB-BONE-EMMC-2G

##Disable HDMI (v3.8.x)

#cape_disable=capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN

##Disable eMMC (v3.8.x)

#cape_disable=capemgr.disable_partno=BB-BONE-EMMC-2G

##Audio Cape (needs HDMI Audio disabled) (v3.8.x)

#cape_disable=capemgr.disable_partno=BB-BONELT-HDMI

#cape_enable=capemgr.enable_partno=BB-BONE-AUDI-02

##enable Generic eMMC Flasher:

##make sure, these tools are installed: dosfstools rsync

##cmdline=init=/opt/scripts/tools/eMMC/init-eMMC-flasher-v3.sh

uuid={removed_from_paste}

`

and here is what I’ve tried

SENDER | RECEIVER | Status
BB UART-4 > Arduino = Fails
Arduino > BB UART-4 = Success

I have tried to transmit from BB both in python (code below) as well after following setup:

stty -F /dev/ttyS4 9600 echo "test" > /dev/ttyS4 echo test > /dev/ttyS4 sudo echo "test" > /dev/ttyS4 sudo echo test > /dev/ttyS4
but nothing appears on Arduino side

I have tested UARTs on Arduino so they do get/read data, with 2 arduinos connected to eachother and it all works.
Tho transmitting from BB does not. I dont have any logic analyzer to verify BB side unfortunately :confused:

For additional info, heres my python2 script on BB:

`

root@beaglebone:~/pyy# cat ser.py

import time

import serial

ser = serial.Serial(

port=’/dev/ttyS4’,

baudrate=9600

)

ser.isOpen()

out=[]

while 1 :

if ser.inWaiting() > 0:

for c in ser.read():

if c != ‘\x02’ and c != ‘\x06’ and c != ’ ':

out.append©

if c == ‘\n’:

cmd=’’.join(map(str,out))

print cmd

if cmd==“quit\r\n”:

ser.close()

print “closing…”

exit

ser.flushInput()

ser.write(“test”)

ser.write(‘test1\n\r’)

out=[]

`

And Arduino is set to read and transmit, Pins are correctly setup

`

#include <SoftwareSerial.h>
SoftwareSerial mySerial(10, 11); // RX, TX
int debug = 0;
void setup() {
mySerial.begin(9600);
Serial.begin(9600);
pinMode(13,OUTPUT);
mySerial.println(“Hello, world?”);
}

void loop() { // run over and over
mySerial.listen();
char nn = mySerial.read();
if(nn > -1){
Serial.println(nn,HEX);
return;
}
}

`

And here’s the schematic:

Really thankful for guidance since ive probably fried UART-2 pins as i accidentaly had levelshifter A-side powered from 5V and UART-1 is occupied by can-tranceiver.