TMS320F2803x intermittent i2c problem at elevated temperature

Ozan Perincek

Hi,

I am experiencing i2c problems when trying to write data to EEPROM using the TMS320F2803x.

At room temperature i2c communication appears to be OK. However, as the temperature is increased (to approx 100 degree C) write and reads to / from EEPROM fails. I have noticed that i2c interrupts are no longer generated when this problem occurs. If I reset the firmware the problem persists. When the chip is cooled to room temperature and reset, it operates correctly again.

All other functionality (driving motors, rs485 communications...etc) are operating correctly at 100 degree C. Only i2c fails.

Has anyone experienced similar problems? The chip I am using (TMS320F28035PAGT) is rated at 105 degree C, so I am running close to the limit, but not over. Is i2c hardware more susceptible to temperature?

Cheers,

over 16 years ago

0 Frank Bormann over 16 years ago

Mastermind 7585 points

Ozan,

what pullup-resistors do you use at the I2C lines?

The I2C timing is very sensitive with these values. It is not sufficient to rely on the internal pullups only.

I would recommend to measure the I2C timing on SCL and SDA at high temperature (or better in the whole operating area).

Regards

0 Ozan Perincek over 16 years ago in reply to Frank Bormann

Prodigy 110 points

Hi Frank,

Thanks for the quick reply. The problem is diagnosed. For those interested; the delay between page / byte writes was set just on the border (at max write cycle time for the EEPROM). It appears at temperature slightly more time is required between writes. The EEPROM was locking-up and latching the data bus to a low state.

Cheers,

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TMS320F2803x intermittent i2c problem at elevated temperature