ATmega48 datasheet(328/340 Pages) ATMEL

328 / 340 page

328

7530H–AVR–02/09

ATmega48/88/168 Automotive

33. Errata ATmega48

The revision letter in this section refers to the revision of the ATmega48 device.

33.1

Rev. E

• Interrupts may be lost when writing the timer registers in the asynchronous timer

1. Interrupts may be lost when writing the timer registers in the asynchronous timer

If one of the timer registers which is synchronized to the asynchronous timer2 clock is written in

the cycle before an overflow interrupt occurs, the interrupt may be lost.

Problem Fix/Workaround

Always check that the Timer2 Timer/Counter register, TCNT2, does not have the value 0xFF

before writing the Timer2 Control Register, TCCR2, or Output Compare Register, OCR2.

33.2

Rev. D

• Interrupts may be lost when writing the timer registers in the asynchronous timer

• POR sensitivity with Vcc ramp up from a very low supply voltage

1. Interrupts may be lost when writing the timer registers in the asynchronous timer

If one of the timer registers which is synchronized to the asynchronous timer2 clock is written in

the cycle before an overflow interrupt occurs, the interrupt may be lost.

Problem Fix/Workaround

Always check that the Timer2 Timer/Counter register, TCNT2, does not have the value 0xFF

before writing the Timer2 Control Register, TCCR2, or Output Compare Register, OCR2.

2. POR sensitivity with Vcc ramp up from a very low supply voltage

If Vcc ramp up from a stable 150mV to 300mV plateau, the Power On Reset (POR) may not

reset the device properly.

Problem Fix/Workaround

None.

33.3

Rev. A

• Interrupts may be lost when writing the timer registers in the asynchronous timer

• POR sensitivity with Vcc ramp up from a very low supply voltage

1. Interrupts may be lost when writing the timer registers in the asynchronous timer

If one of the timer registers which is synchronized to the asynchronous timer2 clock is written in

the cycle before an overflow interrupt occurs, the interrupt may be lost.

Problem Fix/Workaround

Always check that the Timer2 Timer/Counter register, TCNT2, does not have the value 0xFF

before writing the Timer2 Control Register, TCCR2, or Output Compare Register, OCR2.

2. POR sensitivity with Vcc ramp up from a very low supply voltage

If Vcc ramp up from a stable 150mV to 300mV plateau, the Power On Reset (POR) may not

reset the device properly.

ATmega48 Datasheet(PDF) 328 Page - ATMEL Corporation

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