at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 306

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

29. Errata
29.1
29.2
306
Errata AT90PWM81 revA
Errata AT90PWM81 revB
AT90PWM81
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1. Clock Switch enable & disable
2. Crystal oscillator control with Clock Switch
3. BOD disable fuse
4. PSC output at Reset
Available on request
Clock Switch disable
Crystal oscillator control with Clock Switch
BOD disable fuse
PSC output at Reset
Flash and EEPROM programming failure if CPU clock is switched
ADC AMPlifier measurement is unstable
ADC measurement reports abnormal values with PSC2-synchronized conversions
Over-consumption in power down sleep mode
After a “Enable Clock Source” or a “Disable Clock Source” command, the command is still
active until the next access of CLKCSR register. If CLKSEL is written with a new value, the
corresponding clock will be unintentionnaly enabled or disabled.
Work around:
After the Enable or Disable command, write CLKCSR with value 1<<CLKCCE
When a Xtal oscillator is active and CLKSELR is written with a new value for the selection of
another clock source (for instance RC or WD) , the Xtal oscillator gain is not correct.
Work around:
After the commands “Enable Clock Source” and “Clock Source Switching”, write back CLK-
SELR with the values corresponding to the active Xtal oscillator
It is strongly advised to keep the BOD active. Indeed, the RC oscillator may lock if it is acti-
vated when the power suppy goes at a low voltage.
Work around:
If it is mandatory to disable the BOD, do not set the RC oscillator as clock source during
reset and makes sure the RC oscillator is never active when the power supply is below the
lowest POR voltage (2.6V).
At Reset, the PSC outputs may be set at a value different from the PSC Fuse configuration
(Bit 4 of Extended Fuse Byte).
Work around:
Initiate PSC output states from source code.
7734M–AVR–03/10