- About
- Brief information about Pmod HB3
- Interface Description
- Simulation
- Test
- Status Information
- Issues
- Licence
Simple interface for the Digilent Pmod HB3.
The Digilent Pmod HB3 contains a 2A H-Bridge circuit with external feedback to drive small to medium sized DC motors. It has an external voltage source for the DC motor.
Module hb3 provides a motor interface with 256 speed levels. It ensures that no potential short happens within the circuitry, by never changing motor_direction when motor_enable is set. It will clear motor_enable, will change motor_direction next cycle, and then set motor_enable back next cycle if needed. However, it will drive the motor in the opposite direction with speed immediately afterwards. The module also does not have any offset, so for some low speed values the motor may not turn.
| Port | Type | Width | Description |
|---|---|---|---|
clk |
I | 1 | System Clock |
rst |
I | 1 | System Reset |
motor_direction |
O | 1 | Direction Pin for the Motor |
motor_enable |
O | 1 | Enable Pin for the Motor |
direction_control |
I | 1 | Direction Control |
speed |
I | 8 | Speed Control |
I: Input O: Output
On Artix-7:
- Slice LUTs: 15 (as Logic)
- Slice Registers: 10 (as Flip Flop)
- F7 Muxes: 1
Simulation testbench can be found in sim_hb3.v. Testbench simulates various speeds, including full stop and full speed, as well as changing direction in full speed.
Module hb3 direcly with Basys3.xdc. First motor_direction and motor_enable pins are monitored with DDiscovery. After that an actual DC motor with small fan attached to it is tested. 7,5 V power source is attached to motor power pins of the Pmod HB3 Fan attached DC motor begin turning (very slow) when speed was 0x31 (~1.43 V), and was power full enough at 0xFF to move the FPGA, the breadboard and the DC motor itself.
Last Simulation: 28 May 2021, with Vivado Simulator.
Last test: 28 May 2021, on Digilent Basys 3.
CERN Open Hardware Licence Version 2 - Weakly Reciprocal