Hello all. I hope you can help me with a strange situation i have currently.
I have an EVTVDue controller, EVTVDue Microcontroller – EVTV Motor Verks Store This is based on an Arduino Due but a custom PCB with integrated CAN controller.
The issue i'm having is that when i connect it to a laptop, the serial port does not connect. I have installed the IDE on two completely different laptops and get the same error. Based on a very basic sketch that just prints "Hello world" every second, when i view this in the serial monitor or putty, it's just blank. If i try to change the baud it says "Error while setting serial port parameters: 9,600 N 8 1"
The strange thing is, i have tried it on 3 desktop computers and it works fine!!
The first thing i looked at was power. Both a laptop and desktop are supplying 4.55v to the board so no difference there. I have also powered it from a 12v battery and still nothing so i think that rules out power?
Secondly, I have looked at the difference between a laptop and desktop install and both are identical. Using the same driver versions and everything i check matches against the desktop.
I have tried older IDE versions as well as the latest one.
I can upload sketches from all systems no problem.
All computers show the board in device manager as "Arduino Due"
I really don't know what else to try. Can anyone suggest anything?
Hi
True RS232 requires a +/- signal range, where - signifies a negative voltage. Most portables use +V and ground for the two signal levels, and some receivers fail to read that properly. I've fought with this in the past, it's a total pain. Bites when you least expect it.
RS232 is almost as old as me, but twice as fussy to work with!
Reading your post more carefully, your wording is unclear, so I'm not sure this is your issue, but it may be.
Thanks, So if it is power related, how can i fix it? This is going to be plugged into a vehicle for decoding the Can Bus system so it has to run from a laptop somehow.
The EVTVDue board has a specific VIN & GND terminal which i hooked up a 12v battery to and it made no difference.
Turn OFF advanced power settings for the USB ports.
To do that select the USB ports and NOT the "Power Options"
Select Device Manager as that is where you need to work from.
Right click and Properties for the USB ports you want free of power issues.
Select the Power Management tab.
Now deselect the "Allow the computer to turn off this device to save power"
Unfortunately, our usual solution was to change portables, because the devices we were working with couldn't be changed out. Eventually, we simply migrated to USB adapters to RS485 for noise rejection reasons, and put 485->232 adapters at the equipment end as well, and the problems were history.
Sorry, it may not help you, but portable swaps(IIRC, we moved from HP to Dell, but I may be misremembering that, it's more than 15 years ago) is what we did. I do still hear of the problem cropping up from time to time in relation to devices that are true RS232 (bipolar signal), and portables that are not, only 0-> 5V.
And yes, on your portables, turn off all forms of USB power management. There's nothing as scary as a researcher screaming at the top of his lungs "WHERE IS THE (bleeping) DATA FROM LAST NIGHT'S RUN?????". I had EMS on speed dial...