16F877 Flickering LED

[koossa]

I have this strange problem with a RFID Scanner module that I connect to my PIC.

If I connect the RFID Module directly to a 9volt battery and a 7805, it is working fine.

On the RF Reader module I have a LED Witch goes on and off when I scan a RFID.

When I connect the RF Reader Module to PORTA.3 of my PIC through a transistor (To make the current a bit more), the Module's LED Just starts flickering?

Any ideas what the problem could be?

[mister_e]

can you post your whole schematic for some 'visual based' person like me?

[koossa]

Here is my Circuit

[koossa]

Here is the Pin Names for the RFID Reader Module.
I'm ussing a 2N2222A Transistor at the RF Module.

[mister_e]

Depending of your actual code but... did you disable internal adcs?

ADCON1=7

set PORTA.3 to outpuit, set here to LOw at the begining?

are you sure of your actual schematic? looks weird.. What is the part number of your RF module?

[koossa]

Here is my code:




Include "Modedefs.bas"

DEFINE OSC 20 ' Set the Xtal frequency to 20mHz
RFVDDPin VaR PORTA.3 ' RF Module Power Pin.

Main:
ADCON1 = 7 ' Set Analog pins to Digital.
TRISA = 0 ' Set all PortA Pins as output
high RFVDDPin ' Switch RF Module On.
end