AT90S4433_14 Datasheet, PDF (119/126 Pages) ATMEL Corporation – Data and Non-volatile Program Memory

AT90S/LS4433
Errata for
AT90S/LS4433 Rev.
Rev. C/D/E/F
• BOD Keeps the Device in Reset at Low Temperature
• Fuses and Programming Mode
• Incorrect Channel Change in Free Running Mode
• Bandgap Reference Stabilizing Time
• Brown-out Detection Level
• Serial Programming at Voltages below 2.9V
• UART Loses Synchronization if RXD Line is Low when UART Receive is Disabled
7. BOD Keeps the Device in Reset at Low Temperature
When the device operates at low temperature (below 0°C) and the BOD is enabled,
tha part may fail to start up. AT low temperature the BOD may never release the
reset, and the part will not start the application. The problem will only occur during
start-up and an already running application wil not go into reset even if the
temperature goes below 0°C.
Note that this also affects the described workaround for Errata no. 4.
Problem Fix/Workaround
If the device operates at low temperature and a BOD is required, an external BOD
circuit must be used. Alternatively, ATmega8 can be used instead of
AT90S/LS4433.
6. Fuses and Programming Mode
After programming the Fuses in Serial Programming mode, it is not possible to pro-
gram the Flash or EEPROM. If leaving Programming mode, it is not possible to re-
enter Programming mode.
Problem Fix/Workaround
Power the part down and backup again after programming the Fuses or leaving Pro-
gramming mode.
5. Incorrect Channel Change in Free Running Mode
If the ADC operates in Free Running mode and channels are changed by writing to
ADMUX, shortly after the ADC Interrupt Flag (ADIF in ADCSR) is set, the new set-
ting in ADMUX may affect the ongoing conversion.
Problem Fix/Workaround
Use Single Conversion mode when scanning channels, or avoid changing ADMUX
util at least 0.5 ADC clock cycles after ADIF goes high.
4. Bandgap Reference Stabilizing Time
The time for the internal voltage reference for the Analog Comparator to stabilize is
longer than specified. The stabilizing period starts after the bandgap reference has
been selected, and can go on for as much as 10 seconds.
Problem Fix/Workaround
The Bandgap reference will be stable immediately if the internal Brown-out Detector
is enabled.
1042H–AVR–04/03
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