I building a test circuit for an at89c2051 mcu. I want to drive some LED`s with the I/O pins from the controller. In some schematics on the net, I saw that the LED is connected directly to the I/O pin and with a resistor to VCC.
I was not very concentrated last night an connected all resistors directly to the I/O pins and then to he LED`s. Shit happens.
Do I have to remove the parts now and change it?
The 2051 is having the port as open drain. So, connect a series resistor & LED together between the Pin & Vdd. That should solve the problem. A resistor value of approximately 1KΩ will do a nice job. But do try with different combinations. Hope this is helpful...