I have made few different Arduino board which are programmable only via ISP because the Serial communication is giving me this error:
Binary sketch size: 3,026 bytes (of a 30,720 byte maximum) avrdude: stk500_getsync(): not in sync: resp=0x00
Serial communication is wired up wrongly but when I connect my FTDI I just swap the cable, that is not an issue in this case
I have followed the simple schematic of Arduino Nano and Arduino Pro mini which are pretty straight forward.
The AtMega is working, I get the signature and I burnt the bootloader successfully and uploaded the sketch, what I cant understand is why I cant upload my sketch over Serial even if the TX and RX are connected right and RESET is wired as the schematic from Arduino website.
This is the Promini schematic https://www.arduino.cc/en/uploads/Main/Arduino-Pro-Mini-schematic.pdf
Now this board works fine, and the serial communication as well but when I try to upload any sketch , even a simple blinking light, the compiler returns that error above.
Where am I doing wrong? is the wiring of my reset pin wrong? I followed the instruction to add auto-reset and connect to VCC over a resistor.
BTW, it runs at 3.3V and 8mhz, I need to update the schematic.