I have been conducting environmental (temperature) testing for an industrial automation product which uses two processors ( 1 microcontroller and 1 microprocessor).
While in the environmental chamber the MCF51AC256BCLKE works just fine up to +90 deg C before cycling down to -40 deg C. The environmental chamber is set to increment or decrement to temperature in 5 deg/min increments. When the chamber gets down to ~ -10 deg C the MCF51AC256BCLKE stops working (the microcontroller's firmware no longer streams data). The other processor (This is not a Freescale processor) and peripherals continue to work down to ~ -45 deg C. Once the chamber cycles back up to say 0 to +10 deg C the MCFAC256BCLKE starts working again. I have verified that the oscillator for the MCF51AC256BCLKE is still working down to ~ -45 deg C.
Has anyone else seen this type of issue with the MCF51AC256BCLKE? According to the datasheet it is suppose to work across the industrial temperature range of -40 to +85 deg C.