Hi,
Can u post code and hardware?
Check following things.
1. Is LED glowing when u r directly giving 5V supply to it ?
2. Is the voltage on pin is varying (logic 0 and logic 1) as per the program ?
3. If you have connected LEDs on P0, Have u connected external pull up resistor ?
4. Have u provided enough delay between blinking ?
We don’t have any fix issues with 8051 controllers. In market various products are designed with 8051 and it is having a great stability and life time.
Whetehr to continue with 8051 or not is upto you but surely 8051 is great part of Embedded World and we can’t blame on its power. My sir has designed Gold Melting Furnace which can melt 4 kg of gold within few mins and its in use by many of the world known jewellers even today. So definately, 8051 is a powerful and STABLE controller.
But yes, moving towards advanced controller is always a good choice for learning. You can shift to PIC, AVR or even ARM7.
So all the best.