I am new to Arduino having used Xilinx FPGA for most of my computer aided circuit design.
I want to use the PortD = 0bxxxxxxxx command to select pins to run a 3 digit LED display. I will use three other pins to multiplex the display (at least that’s my plan). I am attempting to make a 3 digit readout that will ultimately serve as a counts per second output for a geiger counter I designed and built. I will attempt to get the 3 digit display working on an analog input value first so I can verify my code and so I can make numbers increment with a potentiometer (sounds like fun). Then i’ll write the code to another chip and mount it to a PCB inside my geiger counter (with relevant clock and other discreet parts).
If I use DDRB = B11111111 or pinMode command to set portD as all output, will that block the Tx/Rx port? Isn’t that the port used to program the chip? If I write this code and upload to the Arduino, will I then not be able to rewrite the chip anymore? I considered using a delay(10000) in the setup() section of the code to give a 10 second buffer before the port was taken over so I could modify my code or erase the chip if I needed to. I also thought about just using a 7447 to drive the display, use port B to send the 4 bit value, and use pins on port D to handle the multiplexing. Can someone please help me?