I am using USB2 to supply my Arduino101 which is directly connected to three peripherals:
From specs, I know that Arduino's 3.3 V regulator can provide a maximum of 1500 mA which is more than the total maximum utilized the power of 300 mA.
My program loop stops after a while working correctly. I have checked all variables and looks like this is not a software-related issue.
Can this be a USB's maximum power limitation issue?
mebab:
Can this be a USB's maximum power limitation issue?
Perhaps? USB 1.0 and USB 2.0 ports are capable of delivering up to 500mA, but that requires negotiation between the host and the device.
One thing is what the standards require another thing entirely is what the devices actually do in practice. In my experience the limit is rarely rigorously enforced. So I find it unlikely that's the issue you're dealing with.
An easy way to rule out that issue would be to check wether the device is getting disconnected. If you use Windows you can check the device manager, if you use Linux (Mac?) you can run the command lsusb in a terminal.
mebab:
I know that Arduino's 3.3 V regulator can provide a maximum of 1500 mA
Are you sure that is correct?
On an Uno or Mega it is more like 150mA - perhaps not even that much.
...R
I checked two things:
device manager that shows all USB serial devices are connected despite the program that stops.
SRAM usage where it shows that I have 11940 Bytes free at the end of every loop despite the program that stops.
I cannot figure out what can be the real problem with the board or program that stops after working great for instance 3 hours or less.
mebab:
I cannot figure out what can be the real problem with the board or program that stops after working great for instance 3 hours or less.
Posting your program might be useful.
See How to get the best out of the Forum
...R
Thanks a lot.
nicolajna:
Perhaps? USB 1.0 and USB 2.0 ports are capable of delivering up to 500mA, but that requires negotiation between the host and the device.
One thing is what the standards require another thing entirely is what the devices actually do in practice. In my experience the limit is rarely rigorously enforced. So I find it unlikely that's the issue you're dealing with.
An easy way to rule out that issue would be to check wether the device is getting disconnected. If you use Windows you can check the device manager, if you use Linux (Mac?) you can run the command lsusb in a terminal.
I just tested the system and in the worst situation, the sink current is about 286 mA. I see that when CAM is not connected, the maximum current is 180 mA and the system works for a long time powering from USB2. I am pretty sure now that the CAM is the cause of increasing sink current from USB and the failure.
Quite possibly.
I'm sure there is no standard for power output from a USB port. It might be time to get a proper power supply that tells you what it produces.
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