Datasheet

313
7734Q–AVR–02/12
AT90PWM81/161
4. PSCRRB fuse
When this Fuse bit is programmed in Parallel Programming mode, further parallel and ISP
programming will not program the device correctly.
Work around:
Program the PSCRRB fuse using ISP mode.
5. Over-consumption in power down sleep mode
In Power-down mode, an extra power consumption up to 500µA may occur.
Work around:
No workaround.
27.7 Errata AT90PWM161 revB
• Clock Switch disable
• Crystal oscillator control with Clock Switch
• BOD disable fuse
• PSCRRB fuse
1. Clock Switch enable & disable
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:
Atter the Enable or Disable command, write CLKCSR with value 1<<CLKCCE
2. Crystal oscillator control with Clock Switch
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
3. BOD disable fuse
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 supply voltage (2.6V).
4. PSCRRB fuse
When this Fuse bit is programmed in Parallel Programming mode, further parallel and ISP
programming will not program the device correctly.
Work around:
Program the PSCRRB fuse using ISP mode.