https://learn.adafruit.com/setting-up-i ... black/uart
and changing it to do a loopback read:
Code: Select all
import Adafruit_BBIO.UART as UART
import serial
p = "5"
print "Running UART test on ttyO"+p
UART.setup("UART"+p)
ser = serial.Serial(port = "/dev/ttyO"+p, baudrate=9600)
ser.close()
ser.open()
if ser.isOpen():
print "ttyO"+p+" is open!"
count = 0
ser.write("Hello World!")
while(count < 5):
print(ser.read())
count = count + 1
ser.close()
But when I try it on UART5 I get errors:
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Running UART test on ttyO5
Traceback (most recent call last):
File "utest.py", line 10, in <module>
ser = serial.Serial(port = "/dev/ttyO"+p, baudrate=9600)
File "/usr/lib/python2.7/dist-packages/serial/serialutil.py", line 260, in __init__
self.open()
File "/usr/lib/python2.7/dist-packages/serial/serialposix.py", line 276, in open
raise SerialException("could not open port %s: %s" % (self._port, msg))
serial.serialutil.SerialException: could not open port /dev/ttyO5: [Errno 2] No such file or directory: '/dev/ttyO5'
One hint might be that I don't see ttyO5 here:
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ls -l /dev/ttyO*
crw-rw---- 1 root tty 247, 0 Mar 15 14:36 /dev/ttyO0
crw-rw---T 1 root dialout 247, 1 Mar 15 14:36 /dev/ttyO1
crw-rw---T 1 root dialout 247, 2 Mar 15 14:36 /dev/ttyO2
crw-rw---T 1 root dialout 247, 4 Mar 15 14:38 /dev/ttyO4
my /boot/uboot/uEnv.txt contains this:
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capemgr.enable_partno=BB-UART1,BB-UART2,BB-UART4,BB-UART5