programing ATMEGA 328 using external USB to TTL convertor

Projects Programming
1

Hello all i am new in arduino we purchase arduino demulinove or nano/328 board and one extra boot loader chip .We successfully enter led blink program in board.and then make external led blink circuit and then purchase TTL to usb converter and make connection to my external led blink circuit as follows

usb to TTL converter my led blink circuit

TXD ---------------- RXD
RXD --------------------- TXD
GND--------------------- GND

After that put extra boot loader chip in my circuit and connect USB port and elect same board and port which is generated by external usb to TTL converter .But my program is not downloaded in to chip please help me
it shows following error

Binary sketch size: 4664 bytes (of a 7168 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

2

You need to connect up the DTR line from the converter into the reset line via a 0.1uF capacitor (if there is not one already on the board) to do the auto reset. Otherwise you need to manually hit the reset when you see the message concerning the number of bytes.

3

you also have to use the reset line to auto reset the atmel.
The blink sketch is the default sketch on A arduino rom sow it was there before you prgrammed the microcontroller.
The official schematic of the uno also uses 1K resistors in the data lines like this:

_______ R1
TXD ------|______|---------- RXD

RXD -----|______|---------- TXD
R2
GND--------------------------- GND

DTR ------||-------------- reset (pin1)
C | _______
--------|_______|----------5Volt
R3

C=100N
R1=1K
R2=1K
R3=10K