This will help you upload code to an atmega328p for your standalone arduino project using USB to serial / TTL adapter!
First let’s see if the adapter’s working.
Plug in the adapter >> Open Arduino IDE >> Select the proper COM port >> Open Serial Monitor >> then type in “Hello World”, it should print “Hello World” in the monitor, if not something is wrong
(SKIP THE NEXT STEP IF YOUR ADAPTER IS PROPERLY WORKING)
Step 2: Fixing the Adapter's Driver
Device Manager >> Ports (COM & LPT)
If there is a yellow triangle next to “Prolific USB-to-Serial Comm Port”, that means correct driver version is not installed.
Uninstall your existing driver (Control Panel >> Uninstall a program)
Then install and done!
Do step 1 again to see if the adapter is now working
Step 3: Make the Necessary Wirings
For atmega328p on a breadboard, make the following connections (also, add an LED in series with a 100 ohm resistor on atmega328p pin 19/digital pin 13 for testing later)
1. Pushbutton (normally open)
2. 1 10kohm resistor
3. 2 22pF ceramic capacitors
5. 16 MHz crystal oscillator
Step 4: Atmega328p Pinout
Step 5: Uploading Codes
For uploading code:
1. First make the following connections with the USB to Serial/TTL Adapter
USB to Serial/TTL Adapter >>>Atmega328p
5V >>> 5V rail
GND >>> GND rail
TXD >>> Pin 2 / RX pin
RXD >>> Pin 3 / TX pin
2. Open Arduino IDE >> File >> Examples >> Basics >> Blink
3. Press the pushbutton >> Hit upload
4. Keep on pressing if it says “Compiling sketch…”
5. Release the button as soon as it says “Uploading…”