Hey Sanda,Always refer the | Microcontroller › 8051 › 8051 supply voltage › Hey Sanda,Always refer the March 15, 2013 at 2:05 pm #9322 SavioParticipant Hey Sanda, Always refer the device datasheet to know the absolute maximum ratings. For the AT89c51 MCU the maximum voltage on the VCC pin is 6.6V. But it is better to restrict it to only 5V. Use a 7805 IC if you want to use a 9V source.
