fourletter-phat examples countdown.py fails after random time.
No more than 30 minutes after led goes off.
Sometimes at 14 minutes to the end of countdown sometimes about 20 minutes to the end, random…
The 14 segment led goes off and python reports I/O error.
I am using Raspberry pi 3A+ on latest raspbian.
I am using fourletter library with rainbow hat.
I discover the solution here…
‘IOError: [Errno 5] Input/output error’ while using SMBus for analog reading through RPi
I experienced this problem when driving a 7-segment serial display over I2C with a model b+ rpi. I corrected the problem by adjusting the baud rate to match the device setting (9600). I believe the default is 100000.
To change the baud rate, I added the following line to /etc/modprobe.d/i2c.conf:
options i2c_bcm2708 baudrate=9600
After reboot, I verified the setting had taken effect with:
prompt$ sudo cat /sys/module/i2c_bcm2708/parameters/baudrate
Since then, I’ve had no problems with intermittent I/O errors.
answered Jun 21 2017 at 21:44
On latest raspbian (2019) the solution to random I/O problems with fourletter-phat 14 segment display is…
sudo nano /boot/config.txt
Now, examples fourletter-phat countdown.py works perfect without ramdom errors to led go off.
Hope this helps someone.