DRV10975: How to control the speed bu IIC

Chris Jiang

Prodigy 120 points

Part Number: DRV10975
Other Parts Discussed in Thread: DRV10987,

Hi:

I can used the DRV10975EVB to control the motor speed by IIC .But it do not work in my appylication.

Following is my soft initialization:

1. 0X03 write 0X40 (enable EEPROM config)

2. EEPROM config

0X20:0X6C

0X21:0X07

0X22:0X2C

0X23:0X00

0X24:0X00

0X25:0XD1

0X26:0XE4

0X27:0XFC

0X28:0X53

0X29:0XD8

0X2A:0X09

0X2B:0X4E

3.0X01 write 0X80 (IIC Speed contrl oveRide )

4.0X01 write 0X80

0x00 write 0x96 (write the speed value)

When get into the colosed loop,the Speed is 9360RPM about .And I change the start Speed Value conmand ,when get into the closed loop ,the speed is still 9360RPM about.But,When use the DRV10975EVB ,the same speed value conmand,Speed is 7280RPM.So i think maybe some mistake in my applicaiton ,I can't debug to the speed what I want .Please help me to check it,Also help to check the EEPROM Config whether it is suitable to the Motor,Thanks!

Attachment is my SCH and Motor Spec

Best Regards!

Chris

over 2 years ago

0 Matt Hein over 2 years ago

TI__Mastermind 21805 points

Hi Chris - did you post this question twice? https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1043128/drv10975-how-to-control-the-speed-bu-iic

0 Isaac Lara over 2 years ago in reply to Matt Hein

TI__Mastermind 19610 points

Hello Chris,

Thanks for your posting to the MD forum. It seems like you might have posted twice please let us know so that I may close one of the threads.

Just to note the schematic indicates a DRV10987, it has the same pinout as DRV10975 but I just want to make sure that the DRV10975 is the correct device we are looking at.

Another note: AVSIndEn is not functional on DRV10975, I recommend you disable this which is bit 3 on register 0x27.

On your device configuration I did notice that the Speed pin was configured for PWM mode (bit 1 on register 0x2B) but on the schematic I noticed that it was also pulled up to 3.3V. I believe this might be where you may be having issues with the speed on your device.

If you are configuring speed through I2C you need to ensure that OverRide (bit 7 on register 0x01) is enabled. This ensures that the SPEED pin input is bypassed and the speed is configured through I2C. If you are not using I2C make sure to only feed one signal to the device either an analog voltage or a PWM voltage. If your OverRide bit is not enabled I believe the device is taking PWM from SPEED pin which is tied directly to 3.3V on schematic, which is why the speed wont change. I hope this helps!

Best,

Isaac

0 Matt Hein over 2 years ago in reply to Isaac Lara

TI__Mastermind 21805 points

Closing this thread based on customer input and focusing on the other duplicate thread here: https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1043128/drv10975-how-to-control-the-speed-bu-iic

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DRV10975: How to control the speed bu IIC