I am at a loss as to where to start troubleshooting this issue.
I have Raspberry Pi 4 Compute Module (inside of a Seeed reTerminal) with both UART3 and UART4 enabled, as /dev/AMAtty1 and /dev/AMAtty2, respectively. And am using Node-Red to program it all.
On UART4, I have a TIC500 with an Actuonix S20 Stepper Actuator attached. With assistance from Brandon here @ Pololu on this forum, and a number of other resources, I finally learned how to structure the commands to make this work. And it works very well.
EDIT: Also, am using Pololu Protocol to structure the Serial commands to the TIC.
On UART3, I have a Serial Bus Servo running directly off the Pi, no dedicated controller, which is also functioning well.
Where it gets odd to me, is that if I send a De-energize command to the TIC, afterward, a number of the Servo commands start throwing errors when sent, and the return data from the Servo is invalid. If I then send an Energize command to the TIC all returns to normal. This happens regardless of whether the “Ignore ERR line high” setting is set.
First, in my application, I would prefer not to have the Actuator energized at all times as it gets pretty hot. And second, I do not understand how issuing a command to a device on one UART could impact the operation of a device on another UART.
If anyone can provide any insight and/or direction as to aid in troubleshooting, I would be very appreciative. Also, if I need to provide further information, please let me know.