MCT8329A: i2c problem

Mikael Sundberg

Part Number: MCT8329A

Hi, we have a custom board with a driver on board. We are trying to communicate with the device without any luck. The provided examples in ti documentation is lacking alot of details. We have all voltages ok. The fg and nfault pulled high, the speed command low nd brake high. The i2c is scoped qnd running ok.

We are trying to build an Arduino lib for it.

Do you have any detailed information regarding how to read a simple register?

Just give us one real example of how to set up all ios correctly and how to read a real available register byte for byte. Assume our device address is default value.

Byte1: 0x00

Byte2: OxA0

And so on..

Is crc on per default btw?

Something else we could check? Tje ic seems completely dead and unresponsive.

over 1 year ago

0 Joshua Horlander Cruz over 1 year ago

TI__Mastermind 24740 points

Hi Mikael,

Mikael Sundberg said:
Do you have any detailed information regarding how to read a simple register?

We do have some example code for programming a MCx BLDC motor driver through I2C using the MSP4302355 which you can take a look at: https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1246892/faq-program-mcx-bldc-motor-driver-through-i2c-using-msp430-launchpad.

Mikael Sundberg said:
Is crc on per default

The CRC is enabled per packet by setting the CRC_EN bit in the Control Word (CW22) to 0x1.

In the example code CRC is not supported but by modifying the Control Word being sent and adding another byte read/write operation in the I2C_Read and I2C_Write functions so that they include the CRC byte the code should support CRC.

Mikael Sundberg said:
Something else we could check?

Check that VM > 4.5V, AVDD = 3.3V, and DVDD = 1.5 V. If these voltages meet these requirements then the devices digital core should be active and able to receive input.

Regards,

Joshua

0 Mikael Sundberg over 1 year ago in reply to Joshua Horlander Cruz

Intellectual 730 points

Thanks for the response and I will look into the example code. When you say VM you are talking about the voltage at the motor and PVDD, correct? I think you are looking at the datasheet for the mct8316? PVDD on theMCT8329A?

The problem seems to be with the arduino standard wire library unfortunately. It does not support a delay after sending a message before receiving an ack. So the arduino never sees this. There is no option in that device to inser a delay, like in the provided code example above "#define I2C_TIMEOUT 100000"

I will see if i can make a soft i2c driver and manage this.

0 Joshua Horlander Cruz over 1 year ago in reply to Mikael Sundberg

TI__Mastermind 24740 points

Hi Mikael,

You are correct I meant to say PVDD not VM. Please make sure that PVDD > 4.5V otherwise the device will be in a PVDD undervoltage condition which indicates that the digital core and gate driver are disabled.

Regards,

Joshua

+1 Mikael Sundberg over 1 year ago in reply to Joshua Horlander Cruz

Intellectual 730 points

Hi, I can confirm that it was an i2c issue. I have everything running now. Thanks for the inputs.

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MCT8329A: i2c problem