Unable to use the EVAL6235Q alone or with the STEVAL-PCC009V2

[KSmit.3]

Description:

This is what we did with the EVAL6235Q to use the external speed loop connector to drive a BLDC motor:

1.      On the power supply connector, we attached 12 V.

2.      We connected our BLDC motor to the 3ph BLDC motor connector.

3.      We connected our BLDC motor hall effect sensors to connector J7 pins H1, H2, and H3.

4.      We connected our BLDC motor power pins to connector J7 pins Vdd and GND.

5.      We connected J6 pin 2 and 3 together.

6.      We connected a 3.3 V, PWM (and varied the frequency between 1 to 100 kHz) from a function generator to J8 pin 3 (slout).

After doing the steps 1 to 6 above, the motor would not turn and if we watched the voltage on connector J5 pins OUT 1, OUT 2, OUT3, the voltage was always zero.

Are we doing something wrong or is there a problem with our EVAL6235Q?

This is what we did to try and get the STEVAL-PCC009V2 to work:

We purchased an STEVAL-PCC009V2 (IBU universal interface based on the STM32x) board because it was recommended to be used with the EVAL6235Q board. However, the drivers for this board are written to be used with Window XP or 2000. Our PCs are running Windows 10. In the documentation, it says that when the STEVAL board is connected to the PC that a Window will pop up to walk through installing the drivers. However, this does not happen. Also, after it is connected to the USB port and we open Device Manager and expand the “Universal Serial Bus controllers�?, the “STM32 based IBU UI Tool�? is not shown. The user manual says to contact technical support if this happens.

How should we proceed? Do you have Window 10 drivers? Or do you have an newer communication board?

[Cristiana SCARAMEL]

Hello @KSmit.3​ and welcome to the ST Community.

Some comments:

How did you set the others L6235Q input pins?

By default:

EN is low (pull-down) --> power stage in High Impedance

BRAKE is low (pull-down) --> brake status (HS on)

We connected a 3.3 V, PWM (and varied the frequency between 1 to 100 kHz) from a function generator to J8 pin 3 (slout).

The SLOUT signal is connected to L6235Q through the VREF pin, but this signal must be voltage level (not a PWM).

The connector J8 has been design to make the signals available to implement one external speed loop.(un example of analog speed loop is shown in the L6235Q datasheet figure 17).

Concerning the connection with STEVAL-PCC009V2, did you download the STSW-SPIN003 software and tried to connect the systems?

It is possible the the PC do not "see" the COM port but the system work properly.

Let me know you progress

[KChu.1]

Hello @Cristiana SCARAMEL​ ,

Thanks for the reply.

We set the EN pin to high (5V), and grounded the BRAKE and FW/CCW pins.

Since the SLOUT cannot be a PWM, if we want to control the motor with a PWM signal, should we connect it directly to Vref, which is pin 11 of J3?

As for the STEVAL-PCC009V2. We downloaded the software but would not connect to the board. We tried to install a driver but the driver installer window would not come up.

[Cristiana SCARAMEL]

Hello @KChu.1​ ,

the BRAKE pin if not used must be connected to '5V', if low the device is in brake status (all high-side power MOSFETs on).

If you apply the PWM signal to J3-11, with J6 closed between 1-2, you can low pass filter the signal through R6/R8/C9.

Assuming that the PWM output swings from 0 to 5 V, the resulting Vref is proportional to the PWM Duty cycle:

Vref = (5 V x D x R8) / (R6 + R8)

As for the STEVAL-PCC009V2, I can suggest to update the MCU firmware using the ST-LINK/V2 programmer or an equivalent tool.

You need the STM32CubeProgrammer software and the board firmware STSW-PCC009V2FW