We are making a circuit to run from the atmega328-PU microcontroller chip. I have successfully run the bootloader and can run sketches on the atmega328-PU on a breadboard alone (per Arduino - Setting up an Arduino on a breadboard , using the external clock). However, when I connect the RFID reader RDM6300 using wiring and the basic programming from Arduino Tutorials – Chapter 15 – RFID | tronixstuff.com , the RFID reader does not work. I tried changing the sketch to read pins 0,1 (instead of 2,3; on the atmega328-PU pinout this is pins 2,3 or 4,5) and still no results. The RDM6300 will function when connected to the same chip plugged into a Arduino board (the UNO board, with either a Duemilanove or genuino uno chip), but when it is plugged into a chip on the stand alone bread board it no longer functions (all other sketches tested work, and every other component of this sketch except the RDM6300 read function). We tried to power the stand alone chip with the arduino board 5V supply and still no difference.
Any help is appreciated. I hope that this is a dumb problem, but we have not found a solution after several hours.