Motorola MCU 68HC912D60 Bedienungsanleitung PDF herunterladen (Seite 6)

6 68HC912D60MSE4 Rev 2

March 14, 2001

CGM: STOP DOES NOT TAKE TIME-OUT WHEN RESET CAUSES THE

RELEASE AR431

When coming out of STOP by using reset, the crystal start-up delay time-out does

not occur. This means the MCU may be attempting to run before the crystal has

become stable.

Work-

around

When coming out of STOP with reset, hold the reset signal until the crystal has

reached a stable oscillation.

CGM: CRYSTAL OPERATION AR593

The variation of operational parameters within a given crystal part number may

include a distribution of parts that present impedance conditions at start-up that will

not function with the current design of the CGM. While typical parts may function

correctly, problems may be seen in actual production runs.

Work-

around

Quartz crystal operation should be restricted to maximum 8MHz.

1. Use 8MHz (or slower) oscillator and generate higher bus frequencies using

the PLL module.

2. Use alternative ceramic resonator.

3. Where mimimal clock jitter is critical, use external ’brick’ quartz oscillator

module.

FLASH: CANNOT BE PROGRAMMED RELIABLY AT HIGH TEMPERATURES

AR469

Work-

around

To enhance Flash programming reliability at elevated temperatures, the Flash bulk

erase pulse time (Tepulse) should be reduced from 90-110ms to 5-10ms.

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Motorola MCU 68HC912D60 Bedienungsanleitung Seite 6