Am I right to assume that that VDD does not have to be supplied on the regulated carrier board? Also, is the 5v and 3.3v pins for output or input.
It would be very cool if the logic power was regulated out of the motor supply power and could also be used like a bec to power the microcontroller. Is that possibly the case?
Charlie
Hello, Charlie.
The driver requires a logic supply voltage (3 – 5.5 V) to be connected across the VDD and GND pins. The 5V and 3.3V pins are outputs, so you can use either of them to supply power to VDD. You can also use them to supply logic power to your microcontroller, so long as your microcontroller doesn’t draw that much current.
-Jon
Ok, so if I am understanding you correctly, I could connect both the VDD on the carrier board and the microcontroller (in this case, an Arduino Mino pro) to the 5V output on the carrier. Correct? There is no internal connection between the VDD and the 5v output?
If this is correct, then I could power the a4988 carrier and the Arduino from the motor input power…in this case a 12v lead acid battery without any other power source needed, correct?
Sorry if I am asking what should be obvious, but the little I’ve learned about electronics has pretty much been in a vacuum and I am often surprised at the obvious things I should know but don’t.
Charlie
You could use the 3.3V or 5V pin to supply power to both your microcontroller and VDD on the A4988 carrier. Please note that if you are planning on connecting other peripherals to your microcontroller, it would probably be better to use a separate power supply capable of supplying more current than the 5V or 3.3V regulators on the A4988.
By default, there are no internal connections for VDD. The board is designed to have the 5V or 3.3V output jumpered to the VDD pin adjacent to them. If you are comfortable with soldering, you can use the surface-mount pads to make a solder bridge to your preferred VDD selection. More information on that can be found under the “Power connections” section of that board’s product page.
-Jon
