No, we do not recommend connecting the MC33926 motor driver outputs in parallel to control a single motor, since timing differences in the two units might result in shoot-through. (However, you are correct; the VNH5019 motor drivers are designed so that their outputs can be paralleled.) If your application requires more current than a single driver can handle, you might consider using a higher powered one instead.
It looks like that CNC shield is not using one of our drivers, but in general, you would set the current limit to equal either the maximum rated current of the motor or the driver, whichever is lower. The equation to use for determining what VREF voltage to set on the stepper motor driver board's potentiometer to could be specific to that manufacturer, so you might want to approach them for that information. (The equation for our boards can be found directly on the A4988 carrier's product page.)
Getting an A-Star 32U4 to run on 3.3V at 8 MHz should be possible, but it would not be a straightforward modification since the board was not designed to operate that way. Some of the modifications that immediately come to mind are having to replace the onboard regulator with a 3.3V (or bypass it with an external source), reprogram the fuses on the AVR, and reconfigure the USB connections. If you are interested, a great place to discuss this further would be in our A-Star forum.
The A-Star 32U4 Micro needs at least 5.5 V to function, but we have other low voltage versions such as the A-Star 32U4 Mini LV and the A-Star 32U4 Mini ULV that might work for you. However, please note that those boards do not have any integrated circuitry for LiPo charging or over discharge protection. We do not carry any boards with the LiPo backpack functionality that you mentioned, but we will keep your suggestion in mind.
New product: Pololu Dual MC33926 Motor Driver for Raspberry Pi
- 14 September 2016Hi Karl,
No, we do not recommend connecting the MC33926 motor driver outputs in parallel to control a single motor, since timing differences in the two units might result in shoot-through. (However, you are correct; the VNH5019 motor drivers are designed so that their outputs can be paralleled.) If your application requires more current than a single driver can handle, you might consider using a higher powered one instead.
-Josh
Video: Setting the Current Limit on Pololu Stepper Motor Driver Carriers
- 18 August 2016Hello, David.
It looks like that CNC shield is not using one of our drivers, but in general, you would set the current limit to equal either the maximum rated current of the motor or the driver, whichever is lower. The equation to use for determining what VREF voltage to set on the stepper motor driver board's potentiometer to could be specific to that manufacturer, so you might want to approach them for that information. (The equation for our boards can be found directly on the A4988 carrier's product page.)
-Josh.
New product: A-Star 32U4 Micro
- 23 June 2016Hello, Andrea.
Getting an A-Star 32U4 to run on 3.3V at 8 MHz should be possible, but it would not be a straightforward modification since the board was not designed to operate that way. Some of the modifications that immediately come to mind are having to replace the onboard regulator with a 3.3V (or bypass it with an external source), reprogram the fuses on the AVR, and reconfigure the USB connections. If you are interested, a great place to discuss this further would be in our A-Star forum.
-Josh
New product: A-Star 32U4 Micro
- 22 June 2016Hello, Andrea.
The A-Star 32U4 Micro needs at least 5.5 V to function, but we have other low voltage versions such as the A-Star 32U4 Mini LV and the A-Star 32U4 Mini ULV that might work for you. However, please note that those boards do not have any integrated circuitry for LiPo charging or over discharge protection. We do not carry any boards with the LiPo backpack functionality that you mentioned, but we will keep your suggestion in mind.