[SOLVED]Arduino Promini(MEGA328P U-KP) Sketch not downloaded usign UART.

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1

Hi friends,
I have purchased 10 Arduino pro mino from aliexpress.
8 promini working fine and i am able to load sketch using FTDI adaptor.

i am not able to download sketch on two promini, so i decided to download new bootloader on it.
i have used my arduino uno as programmer and follow below mentinoed steps.
Open arduino IDE(1.8.12)
select board as arduino uno & open example sketch ArduinoISP
Download that sketch on uno.
make connection between Uno and Promini as mentioned below.

Connection detail:-
UNO           Promini
GPIO10      Rst
GPIO11      GPIO11  
GPIO12      GPIO12
GPIO13      GPIO13
VCC           VCC   
GND           GND

Then select bord type as "Arduino Pro or Pro Mini"
Then select processor as "ATmega328p (5V, 16 MHz)"
Then select port as "COM5" its comport on which FTDI adpacotr is connected.
Then select Programmer as "Arduino as ISP"

finally i have executed "Burn Bootloader" commmand and get responce as below & full responce is attached.

avrdude: load data flash data from input file C:\Program Files (x86)\Arduino\hardware\arduino\avr/bootloaders/atmega/ATmegaBOOT_168_atmega328.hex:
avrdude: input file C:\Program Files (x86)\Arduino\hardware\arduino\avr/bootloaders/atmega/ATmegaBOOT_168_atmega328.hex contains 32670 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 0.00s

avrdude: verifying ...
avrdude: 32670 bytes of flash verified
avrdude: reading input file "0x0F"
avrdude: writing lock (1 bytes):

Writing | ################################################## | 100% 0.02s

avrdude: 1 bytes of lock written
avrdude: verifying lock memory against 0x0F:
avrdude: load data lock data from input file 0x0F:
avrdude: input file 0x0F contains 1 bytes
avrdude: reading on-chip lock data:

Reading | ################################################## | 100% 0.01s

avrdude: verifying ...
avrdude: 1 bytes of lock verified


avrdude done.  Thank you.

Then i tried to connect Arduino promini wity FTDI adaptor and tried to downlod example sketch "DigitalReadSerial" but not succeded.
then i connected Arduino promini with Arduino uno which is prepared as ISP programmer and tried to download code using "Sketch > Upload Using Programmer" function. & successfully download sketch.
for checking i have connect arduino promini with FTDI and open serial monitor for checking weather get serial respince or not.
i set baudrate "9600" but i get gibrish responce.
i checked baudrate in sketch which is 9600.

Serial.begin(9600);

Surprisingly i didnot get proper serial responce by setting serial plotter baudrate 9600.
but when i set baudrate of serial plotter to 4800 surprisingly i get serial responce as per code.
what i understand is arduino promini is workng on 8Mhz.

finally i am not able to download sketch using FTDI adaptor but using Arduino UNO as ISP i can download sketch, and UART of Promini is working fine with half of set baudrate.

my question is how to download sketch using UART???
Do i have to change any settign of ArduinoISP sketch or I have to change crystal???

Responce.doc (14.3 KB)

2

Well you can check for sure whether what the Crystal is by using the blink sketch, it should flash the LED at once per second.

What did Aliexpress say when you complained ?

3

srnet:
Well you can check for sure whether what the Crystal is by using the blink sketch, it should flash the LED at once per second.

What did Aliexpress say when you complained ?

I have uploded Blink sketch on one of problemetic promini and compare it wirth my working promini, & i observed blink rate of problemetic promini is half of the normal one.

so i am sure this promini has 8 MHz crystal.

srnet:
Well you can check for sure whether what the Crystal is by using the blink sketch, it should flash the LED at once per second.

What did Aliexpress say when you complained ?

i checked this promini after long time of recieving so there is no point to contact sellar.

Do i have to download sketch usign my uno as ISP???

or

Iis there any way using which i can doenload sketch using FTDI.

4

If its got an 8Mhz crystal fitted, then just use the UNO as ISP to load up the Pro Mini 8Mhz bootloader

5

srnet:
If its got an 8Mhz crystal fitted, then just use the UNO as ISP to load up the Pro Mini 8Mhz bootloader

Did as you suggested & it start working fine.
Thanks