BLDC Open-Loop Control with Speedgoat IO397 and DRV8305

This repository contains a Simulink Real-Time example for open-loop, six-PWM control of a three-phase BLDC motor. It targets a Speedgoat real-time machine fitted with an IO397-50k module, a Texas Instruments BOOSTXL-DRV8305EVM inverter, and a MOONS 42BL30L2 motor.

The model generates a three-phase voltage command, sends six complementary PWM signals to the DRV8305 EVM, measures phase-A and phase-B current, and can measure rotational speed from one motor Hall channel.

Safety: This is an open-loop demonstration, not a production motor drive. Begin with a current-limited, low-voltage DC supply. Keep the gate driver disabled until all PWM, ground, power, and feedback connections have been checked with the DC bus off.

Repository contents

File	Purpose
speedgoat_IO397_RCP_BLDC_openloop.slx	Main Simulink Real-Time model
speedgoat_IO397_RCP_OpenLoop_Initialize.mat	Model parameters and initialization data
speedgoat_drv8305_wiring_interface.md	Detailed pin mapping, wiring notes, and commissioning procedure
speedgoat_drv8305_wiring_diagram_v2.png	Speedgoat-to-DRV8305 wiring diagram
speedgoat_42bl30l2_hall_speed_wiring.png	42BL30L2 Hall-to-Speedgoat speed measurement diagram

Wiring diagrams

Speedgoat IO397 to DRV8305 EVM

Motor Hall speed measurement

See speedgoat_drv8305_wiring_interface.md for the complete pin tables and electrical notes.

Hardware requirements

Required

• Speedgoat real-time target machine with an IO397-50k configurable I/O module.
• Host computer connected to the Speedgoat target over Ethernet.
• Texas Instruments BOOSTXL-DRV8305EVM three-phase inverter board.
• MOONS 42BL30L2 BLDC motor:
  • 24 VDC
  • 30 W
  • 6 poles / 3 pole pairs
  • 4000 rpm rated speed
  • 5000 rpm maximum speed
• Current-limited DC power supply suitable for the motor and inverter. Use a reduced bus voltage and conservative current limit for initial commissioning.
• Wiring for six PWM signals, gate enable, digital ground, motor phases, Hall supply/ground, and the selected Hall output.
• Appropriate mating connectors or breakout cables for the Speedgoat IO397 and DRV8305 EVM headers.

Strongly recommended

• Oscilloscope with suitable probes for checking PWM signals, dead time, Hall output level, and gate-driver behavior.
• Bench multimeter.
• Fuse or resettable protection in the DC-bus supply path.
• Accessible emergency stop or DC-bus disconnect.
• Mechanical restraint or guarded motor mounting.
• Logic-level conditioning or a pull-up resistor if the measured Hall output requires it.

Optional protection connections

• DRV8305 nFAULT to Speedgoat Digital B pin 15 / DIO13 (*Optional). The present model does not act on this signal; a digital input block and shutdown logic must be added before it can automatically disable EN_GATE.
• DRV8305 PWRGD to a spare input or oscilloscope (*Optional).

Software requirements

This repository was inspected and verified with the following installed environment:

Product	Verified version
MATLAB	R2025b Update 5
Simulink	R2025b
Simulink Real-Time	R2025b
Simulink Coder	R2025b
Motor Control Blockset	R2025b
C2000 Microcontroller Blockset	R2025b; reported by model dependency analysis
Speedgoat I/O Blockset	9.11.1 for R2025b
Speedgoat I/O Configuration Package	9.11.1 with the IO397 RCP configuration

The model uses the Simulink Real-Time system target file speedgoat.tlc and the prebuilt IO397 RCP bitstream:

C:\ProgramData\Speedgoat\bitstreams\io_configuration_package\R2025b\io397\speedgoat_IO397_RCP.mat

If another MATLAB release is used, install the matching Speedgoat packages and select the corresponding release-specific bitstream path in the model's Setup block. HDL Coder is not required when using the supplied prebuilt bitstream; it is needed only if the FPGA configuration is customized and rebuilt.

Model configuration

The supplied model is configured as follows:

• Simulink Real-Time target: speedgoat.tlc
• Solver: fixed-step discrete
• Stop time: infinite
• Control/PWM sample time: 50 microseconds
• PWM frequency: 20 kHz
• FPGA clock: 75 MHz
• Motor pole pairs: 3
• Initial speed reference in the model: 500 rpm
• Initial voltage amplitude (Boost Voltage): 0.15 per unit
• Initial Start value: 0, which keeps the drive disabled

The initialization MAT-file defines PWM_frequency, T_pwm, Ts, dataType, motor, inverter, and target. Its target.model field contains a legacy C2000 value and does not select the Speedgoat real-time target; the Simulink model configuration and Simulink Real-Time target object control deployment.

First-time setup

1. Install MATLAB, the required MathWorks products, and the matching Speedgoat software packages.
2. Connect the host computer to the Speedgoat target and verify that it appears in Simulink Real-Time Explorer.
3. Confirm that the IO397 RCP bitstream file exists at the path configured in the model's Setup block.
4. Complete the power, PWM, enable, ground, motor phase, and feedback wiring using the supplied diagrams.
5. Keep the DC bus switched off and leave the model Start value at 0.
6. Open MATLAB and make this repository the current folder.

Load the initialization data and open the model:

load('speedgoat_IO397_RCP_OpenLoop_Initialize.mat');
open_system('speedgoat_IO397_RCP_BLDC_openloop');

Build and deploy

1. In the model, open the Setup block and confirm:
   • Board: IO397-50k
   • Bitstream: speedgoat_IO397_RCP.mat
   • Bitstream directory matches the installed MATLAB/Speedgoat release.
2. Select the correct Speedgoat target in Simulink Real-Time.
3. Build the real-time application from the Real-Time tab.
4. Load the application onto the Speedgoat target.
5. Start the real-time application while Start = 0 and the inverter DC bus remains off.
6. Check that the application runs without I/O or bitstream errors.

Motor and power-stage connections

The initial phase assignment is:

42BL30L2 phase connector	DRV8305 EVM
Pin 2, orange — U	J4 pin 3 — MOT_A
Pin 3, yellow — V	J4 pin 2 — MOT_B
Pin 1, blue — W	J4 pin 1 — MOT_C

If the rotation direction is opposite to the requested direction, change the commanded phase sequence. Do not randomly exchange Hall wires.

Hall speed measurement

QAE is a quadrature encoder generator and is not used for measuring this motor. The model uses a QAD block to decode an incoming signal.

The motor's Hu, Hv, and Hw signals are 120-electrical-degree commutation signals, not 90-degree quadrature A/B signals. For speed-only measurement, use one Hall channel:

42BL30L2 Hall connector	Speedgoat IO397
Pin 1, red — VCC	Digital B pin 2 — +5 VDC
Pin 5, black — GND	Digital B pin 17 — GND
Pin 6, orange — Hu	Digital B pin 10 — QAD channel 1 A
Pin 3, yellow — Hv	Not connected; insulate the wire
Pin 4, blue — Hw	Not connected; insulate the wire
Pin 2	NC

Configure QAD channel 1 as follows:

Parameter	Setting
Captured Signal Edges	Capture Rising Edges A Signal Only
Number of Slots Vector	3
Index Control Mode	Ignore Index
QAD-B and QAD-index	Leave unconnected

For one Hall channel and three pole pairs:

RPM = 60 × Hall frequency / 3
RPM = 20 × Hall frequency

Expected Hall frequencies are approximately 200 Hz at 4000 rpm and 250 Hz at 5000 rpm.

The motor drawing does not specify whether the Hall outputs are push-pull or open-collector. Before connecting Hu to the IO397, power the Hall sensors and inspect Hu with an oscilloscope. Match the IO397 3.3 V/5 V TTL pull configuration to the observed output type and voltage.

Safe commissioning procedure

1. Switch off and discharge the inverter DC bus.
2. Verify continuity and pin numbers for all six PWM wires, EN_GATE, digital ground, motor phases, current feedback, and Hall wiring.
3. Keep Start = 0 and initially disconnect the motor power stage if practical.
4. Run the real-time application and inspect all six PWM signals with an oscilloscope.
5. Verify complementary high/low operation and adequate non-overlap before applying significant bus voltage.
6. Apply a low, current-limited DC-bus voltage. Confirm the EVM supply rails, PWRGD, and nFAULT state.
7. Connect or energize the motor with the voltage amplitude at its low initial value and the speed reference at a conservative value.
8. Change Start to 1 only after the PWM and feedback signals are valid.
9. Increase voltage amplitude and speed gradually while monitoring DC-bus current, phase-current feedback, motor temperature, and measured speed.
10. If nFAULT asserts, current rises unexpectedly, the motor stalls, or the phase signals are incorrect, set Start to 0 and remove DC-bus power immediately.

Current feedback notes

The model reads phase-A and phase-B current from the DRV8305 EVM. It uses offsets of 1.6945 V and 1.6930 V and a scale factor of 14.286 A/V. With the motor power disabled, confirm that both displayed current values are close to zero. Recalibrate the offsets if necessary before powered testing.

Known limitations

• Control is open-loop; the measured Hall speed is for observation and is not used to close the speed loop.
• The model does not currently process nFAULT or PWRGD.
• The IO397 RCP bitstream does not provide SPI control for this example. The DRV8305 register configuration and detailed diagnostics are therefore not managed by the model.
• FPGA PWM deadband is configured as zero. Confirm that the DRV8305 dead-time/handshake behavior provides safe switching before increasing bus voltage.
• Only two phase-current signals are measured.
• One Hall channel provides speed magnitude but not independent direction information.

Reference hardware

• MOONS 42BL30L2 motor
• Speedgoat IO397 module
• TI BOOSTXL-DRV8305EVM