I've made a development board for ATmega328P like Arduino Uno.


Fig. 1 - schematic

bottom layer

Fig. 2 - bottom layer

top layer

Fig. 3 - top layer

I am able to upload the code using FTDI chip (I've used the chip which has boot loader in it). However the code is not working; I mean the LED connected to pin 14 is not blinking.

When I check the supply voltage at pin 7 I get 4.9 V, but when I check the same at GPIO it is giving 0.3 V.

I'm new to PCB designing. Please let me know what could have gone wrong.

void setup() {
   pinMode(14, OUTPUT);

// the loop function runs over and over again forever
void loop() {
    digitalWrite(14, HIGH);   // turn the LED on (HIGH is the voltage level)
    delay(1000);              // wait for a second
    digitalWrite(14, LOW);    // turn the LED off by making the voltage LOW
    delay(1000);              // wait for a second


  • \$\begingroup\$ Have you set the configuration bits? I guess the controller is not running. \$\endgroup\$
    – Mike
    Oct 20, 2020 at 5:40
  • \$\begingroup\$ hello Mike yes, also even if i use the flased controller from uno . it will not work. \$\endgroup\$
    – Anil Suha
    Oct 20, 2020 at 5:42
  • \$\begingroup\$ @Sanmvegsaini what is R5 then? ... looks like a pullup on the reset line to me \$\endgroup\$
    – jsotola
    Oct 20, 2020 at 5:47
  • 4
    \$\begingroup\$ your code is wrong pinMode(8, OUTPUT) sets physical pin 14 of ATMEGA328 as output on Arduino UNO \$\endgroup\$
    – jsotola
    Oct 20, 2020 at 5:53
  • 1
    \$\begingroup\$ google arduino uno schematic \$\endgroup\$
    – jsotola
    Oct 20, 2020 at 7:31

1 Answer 1


The code is wrong because you are using the pin physical of the microcontroller like an Arduino pin. You need to review ATmega168/328P-Arduino Pin Mapping able on the Arduino web page

ATmega168/328P-Arduino Pin Mapping

I recommend you to review the source code where these pins are defined pins_arduino.h - Pin definition functions for Arduino


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