MCT8316Z: FAULT & OTP_ERR bits on, motor not spinning

Josef Novak

Part Number: MCT8316Z

Hey guys and gals!

I've made myself a nice little eval board to test the MCT8316ZR (SPI version). After a couple of hours of successful experimenting I keep getting the FAULT flag always on (also seen in status register 0) and the motor stopped spinning. From the status register 2 (datasheet table 8-15 on page 66) I see the OTP_ERR flag is on.

There is no further information on "One time programmability error" in the datasheet. What is does OTP error stand for? What is here one-time-programmable?

Attempts to clear the fault (CLR_FLT bit in Control Register 2A (tab 8-19, p 69) does not result into any change in behaviour nor does the nSleep reset pulse. What am I doing wrong? How to fix it?

Status registers:
       #0: 0x01 0b00000001
       #1: 0x00 0b00000000
       #2: 0xC0 0b11000000

Many thanks for any insights!

Pepa

over 2 years ago

0 Joshua Horlander Cruz over 2 years ago

TI__Mastermind 24200 points

Hi Pepa,

Is this OTP_ERR error flag appearing on just one device or multiple devices?

Also just to confirm, is this OTP_ERR error flag still appearing after the device has been power cycled?

Regards,

Joshua

0 Josef Novak over 2 years ago in reply to Joshua Horlander Cruz

Prodigy 50 points

Hi Josh,

it is just one chip. The setup is to evaluate whether to use the HW or SPI version.

Power cycling does not help, even the next day it behaves the same (if that was an overheating issue).

In some other thread I've discovered there is some kind of OTP memory which is not user-accessible. Might that be anyhow related?

Cheers,

Pepa

0 Joshua Horlander Cruz over 2 years ago in reply to Josef Novak

TI__Mastermind 24200 points

Hi Pepa,

OTP_ERR indicates that the One Time Programable memory of the device did not program correctly at production. Unfortunately OTP is unmodifiable meaning the device can no longer be used.

I assume this is the thread you are referring to but here is a thread with a bit more information on this topic: MCT8316Z: One Time Programmabilty Error / Schematic Review

Regards,

Joshua

0 Josef Novak over 2 years ago in reply to Joshua Horlander Cruz

Prodigy 50 points

It actually was this one: [e2e.ti.com/.../drv8316-regarding-otp]

But that is most likely unrelated.

When the flags are as they are, is there any other way to troubleshoot what might cause the problem?

nFault is held high on power-up to avoid entering the "internal test mode". How would one recognize if the chip was in such state?

Br,

Pepa

0 Joshua Horlander Cruz over 2 years ago in reply to Josef Novak

TI__Mastermind 24200 points

Hi Pepa,

Josef Novak said:
When the flags are as they are, is there any other way to troubleshoot what might cause the problem?

The OTP_ERR flag bein raised means that the OTP memory experienced an error when it was programmed during production. The device that is raising this flag can no longer be used.

Josef Novak said:
nFault is held high on power-up to avoid entering the "internal test mode". How would one recognize if the chip was in such state?

To check if you are in internal test mode you can see if any fault can be triggered, like an under voltage fault. If you are getting faults then you are not in test mode.

Regards,

Joshua

0 Josef Novak over 2 years ago in reply to Joshua Horlander Cruz

Prodigy 50 points

Joshua Horlander Cruz said:
The OTP_ERR flag bein raised means that the OTP memory experienced an error when it was programmed during production. The device that is raising this flag can no longer be used.

The chip was driving the motor for several consecutive hours before the OTP_ERR occurred. Meaning it was not there from the production. That would mean there is another way to introduce the error.. Or might it been a (potentially) faulty chip in which the memory failed after a while? This might be be rather unpleasant behaviour for further product production :|

Either way, I will obtain a new one and we will see how long will that one work.

A last question regarding the OTP memory: is it present also in the HW (-ZT) chip? Might this problem pop-up also with this IC?

With kind regards,

Pepa

0 Joshua Horlander Cruz over 2 years ago in reply to Josef Novak

TI__Mastermind 24200 points

Hi Pepa,

Josef Novak said:
A last question regarding the OTP memory: is it present also in the HW (-ZT) chip?

OTP memory is also present in the HW variant of the MCT8316Z.

Josef Novak said:
might it been a (potentially) faulty chip in which the memory failed after a while?

I will need some time to look into this. I will aim to get back to you by Wednesday of next week.

Regards,

Joshua

0 Joshua Horlander Cruz over 2 years ago in reply to Joshua Horlander Cruz

TI__Mastermind 24200 points

Hi Pepa,

It is possible that the memory in the the device failed after a while but we cannot definitively say.

Regards,

Joshua

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MCT8316Z: FAULT & OTP_ERR bits on, motor not spinning