Editing Openai/692da612-aac4-800b-80dd-f1568632e2ff (section)

== gpt-5-t-mini ==
=== User: uno ===
uno
com6
its on but not blinking

=== Assistant: Nice — thanks. ===
Nice — thanks. You gave everything I need. Below is a focused checklist + precise steps (most fix the Access is denied / upload fail problem) and a tiny Blink test sketch so you can try uploading. Follow steps in order until it works.

=== 1. Unplug the UNO. Wait 5s. Re-plug to a different USB port on your PC (prefer rear port if desktop). ===
# Use a data USB cable (not a charge-only cable). Try another cable if in doubt.
# Make sure only one Arduino IDE / Serial Monitor / Python script is open. Close all Serial Monitor windows.
# In Arduino IDE → Tools → Board select Arduino Uno.
# In Arduino IDE → Tools → Port select COM6 (Arduino Uno) — NOT other COMs.

=== Right-click Arduino IDE → Run as administrator. ===
Try upload again. Many "Access is denied" errors vanish after this.

=== - Open Device Manager → Ports (COM & LPT). ===
* Confirm Arduino Uno (COM6) (or CH340/USB-SERIAL (COM6)).
* If it shows an exclamation mark, right-click → Update driver → Search automatically (or uninstall device → unplug → replug).

If Device Manager shows a different COM number after replugging, pick that number in Arduino IDE.

=== Programs that lock COM ports: Serial Monitor, PuTTY, CoolTerm, VS Code serial terminals, PlatformIO, any Python script. ===
Open Task Manager and end suspicious processes (python.exe, putty.exe, etc.) if necessary.

=== Some clones need the reset timed manually: ===
# Click Upload in Arduino IDE.
# When status says Uploading... (or when compilation finishes and IDE shows “Uploading”), press and release the RESET button on the UNO. This toggles the bootloader and may allow upload.

=== Sometimes other USB-serial devices take control of drivers. Unplug other USB-serial adapters, phones, etc. ===

=== If you can, plug the UNO into another computer with Arduino IDE installed. If it uploads there, problem is on your PC (driver/permission). ===

=== - Genuine UNO uses ATmega16U2 — Windows usually handles it automatically. ===
* Cheap clones often have CH340 or CP2102 USB-serial chips and need drivers. If Device Manager shows unknown device, install CH340/CP2102 drivers (search “CH340 driver Windows” or “CP2102 driver Windows”) and reboot. (I can give exact driver links if you want.)

=== - If no RX/TX blink during upload attempt, the bootloader may not be running or ATmega328P may be dead/disconnected. ===
* If you have another working Arduino UNO, you can try Upload Using Programmer / Use as ISP to re-burn the bootloader. I can give step-by-step for that if you want.

=== 1. Unplug board. Connect a jumper from RX to TX on the UNO (pins 0 and 1). ===
# Open Arduino IDE Serial Monitor on COM6 at 9600. Type something — if what you type appears back, the serial interface is working.
# Remove jumper after testing.

=== 1. Open a new sketch, paste this, then try Upload. ===

<syntaxhighlight lang="cpp">// Simple Blink test to verify upload
void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  delay(400);
  digitalWrite(LED_BUILTIN, LOW);
  delay(400);
}

</syntaxhighlight>
* If this uploads successfully, LED on pin 13 should blink.
* If upload still fails with the same avrdude error, continue using the checklist above.

=== - How to reinstall CH340/CP2102 drivers step-by-step. ===
* How to identify which process is locking COM6 (Windows method).
* How to burn the bootloader using another Arduino as ISP (step-by-step).
* Suggest specific replacement cables/ports to try.

Tell me which step you tried and what happened (e.g., “ran IDE as admin — same error”, or “tried another cable — now UNO COM changed to COM4”), and I’ll give the exact next command or step.

=== User: Sketch uses 2100 bytes 6% of program storage space. ===
Sketch uses 2100 bytes (6%) of program storage space. Maximum is 32256 bytes.
Global variables use 294 bytes (14%) of dynamic memory, leaving 1754 bytes for local variables. Maximum is 2048 bytes.
avrdude: ser_open(): can't open device "\\.\COM6": Access is denied.

Failed uploading: uploading error: exit status 1

=== Assistant: Good — you’ve confirmed the sketch compiles and the error happens only at upload. ===
Good — you’ve confirmed the sketch compiles and the error happens only at upload. That means the Arduino / bootloader is probably fine and the problem is Windows / COM port access. Below I’ll give a short, ordered checklist with exact actions to try (do them in order). Follow each item and try uploading after the step that mentions “Try upload now.”

==== - Completely close Arduino IDE first. ====
* Close any terminal apps (PuTTY, Tera Term), VS Code, PlatformIO, Python scripts, Serial Monitor windows.
* Open Task Manager → Processes → look for python.exe, putty.exe, node, Code.exe etc. Right-click → End task for anything that might open serial ports.

Try upload now.

==== - Right-click Arduino IDE → Run as administrator → open your sketch → Tools → Port → choose COM6 (Arduino Uno) → Upload. ====

Try upload now.

==== - Unplug UNO → change to a different physical USB port on the PC (prefer rear ports). ====
* Use a different USB cable (must be data cable).
* Re-plug UNO. Wait ~5s for drivers to re-initialize.
* Confirm Device Manager → Ports (COM & LPT) shows Arduino Uno (COM6). If COM changed, select that port in Arduino IDE.

Try upload now.

==== Windows doesn’t show this directly. Use Process Explorer (Sysinternals) or handle.exe: ====

Process Explorer method (recommended)
# Download & run Process Explorer from Microsoft Sysinternals.
# Press Ctrl+F (Find) → type COM6 → it will list the process holding a handle to COM6.
# If a process is listed, select it in Process Explorer → right-click → Kill Process.

handle.exe method
# Download handle.exe from Sysinternals.
# Open Command Prompt as Administrator and run:

<syntaxhighlight>handle.exe -a COM6

</syntaxhighlight>

It will list process IDs using COM6. Kill the processes (Task Manager).

Try upload now.

==== 1. Open Device Manager → Ports (COM & LPT). ====
# Right-click the Arduino device (COM6) → Uninstall device.
# If there’s a checkbox Delete the driver software for this device, check it.
# Unplug Arduino, wait 3–5s, plug it back in. Windows will reinstall drivers.

Try upload now.

==== 1. Device Manager → Ports → Right-click Arduino → Properties → Port Settings → Advanced... ====
# In COM Port Number select an unused port (e.g., COM3 or COM4). Click OK.
# Select that new port in Arduino IDE → Tools → Port.

Try upload now.

==== - If Device Manager shows CH340 or USB-SERIAL, reinstall the correct driver: - Uninstall device (see step 5) and choose Delete driver software if available. - Reboot PC and let Windows reinstall, or install the vendor driver (CH340/CP2102). (I can give exact driver links if you want.) ====

Try upload now.

==== 1. Power OFF Arduino. Place a jumper between TX (pin1) and RX (pin0). ====
# Power ON Arduino. Open Serial Monitor on the COM shown in Device Manager at 9600.
# Type something — if you see it echoed back, the USB-serial interface is OK.
# Remove jumper afterwards.
* If loopback fails, problem is with the USB-serial chip/driver/cable.

==== - When you press Upload, watch the RX/TX LEDs: if they do not flash at all, the PC is not talking to the board. That points to driver/COM lock/cable problems. ====
* If they flash during upload but upload still fails, note exact behavior and tell me.

==== - Try the UNO on another PC — if it uploads there, the problem is on your Windows machine. ====
* If you have another UNO, try uploading to that board to isolate the hardware.

===== - After trying steps above, tell me the first step that changed behavior (e.g., “Process Explorer showed python.exe holding COM6 and killing it fixed upload”, or “Loopback test failed”, or “No change after all steps”). =====
* If Device Manager shows the device name under Ports, paste the exact text shown (e.g., Arduino Uno (COM6) or USB-SERIAL CH340 (COM6)).

If you want, I can give step-by-step for Process Explorer or driver reinstall with exact clicks — tell me which one you want and I’ll write the exact steps.

=== User: Sketch uses 924 bytes 2% of program storage space. ===
Sketch uses 924 bytes (2%) of program storage space. Maximum is 32256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes.

The led isnt blinking when i gave code for led blinking, but the red light on arudino uno is blinking. Ig it is not genuine part what to do nect

=== Assistant: Good — useful info. ===
Good — useful info. Sounds like the sketch compiled but the board didn’t actually run it (LED on pin 13 didn’t blink). The blinking red power LED just means the board is powered — not that your sketch ran. Below is a short, ordered troubleshooting plan (start at step 1 and stop when you see the built-in LED blink). I’ll include exact tests you can run and what to do if the board is a clone or faulty.

=== 1. Open Arduino IDE → toggle Verbose output during upload: File → Preferences → check “Show verbose output during: upload”. ===
# Upload the Blink sketch again (File → Examples → 01.Basics → Blink).
# Watch the IDE console at the bottom. Successful upload ends with something like: Done uploading. If you still see the avrdude COM error, go back to the COM/driver checklist we used earlier.

If upload shows Done uploading proceed to step 2.
If upload fails, you still have a COM/driver/bootloader issue — see step 6 (re-burn bootloader) or try the alternate PC.

=== When you press Upload, the RX/TX LEDs should flash rapidly during upload. ===
* If RX/TX do flash but LED13 still doesn’t blink → sketch uploaded but hardware pin 13/LED may be disconnected.
* If RX/TX do NOT flash → the PC didn’t talk to the bootloader (driver/COM/lock problem).

=== Paste this in a new sketch and upload — it toggles pin 13 AND prints values to Serial: ===

<syntaxhighlight lang="cpp">void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(9600);
  Serial.println("Start test");
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  Serial.println("HIGH");
  delay(500);
  digitalWrite(LED_BUILTIN, LOW);
  Serial.println("LOW");
  delay(500);
}

</syntaxhighlight>
* Open Serial Monitor at 9600.
* If Serial Monitor prints HIGH/LOW but built-in LED still doesn’t blink, the LED or its trace / resistor on the board is damaged.
* If Serial Monitor prints nothing and upload showed “Done uploading”, that suggests the sketch didn’t actually run (boot problem) or Serial is on the wrong port.

=== - Many UNO clones wire the onboard LED to pin 13 differently or have poor solder joints. Test with an external LED: 1. Connect a normal LED (with 220Ω resistor) from pin 13 → resistor → LED (long leg), LED short leg → GND. 2. Upload the Blink sketch again. 3. If the external LED blinks but the onboard LED does not → onboard LED or solder trace is faulty (board hardware issue). 4. If external LED also does not blink → upload/run problem. ===

=== This verifies the USB-to-serial interface is okay (useful for clones): ===
# Power OFF board. Put jumper wire between TX (pin1) and RX (pin0).
# Power ON board. Open Serial Monitor at any baud (9600).
# Type into monitor → if you see your typed chars echoed back, USB-serial is OK.
# Remove jumper after test.
* If loopback fails → driver or USB-serial chip (CH340/CP2102) problem. Reinstall driver or replace board.

=== If uploads appear to finish but board never runs sketches, the ATmega328P bootloader may be corrupted or the MCU may be faulty. ===

If you have another Arduino you can re-burn the bootloader:
* Use another UNO as ISP and Tools → Burn Bootloader (I can give step-by-step instructions if you want). If you don’t have another Arduino, you can use an ISP programmer or buy a replacement ATmega328P pre-loaded.

=== - Measure the board’s 5V with a multimeter between 5V and GND — must be ≈5V. ===
* Inspect solder joints around the 328P socket (if DIP) or the surface mount pins. Cold joints or lifted pads are common on cheap clones.

=== If Device Manager shows CH340 or CP2102, ensure correct drivers are installed. A missing driver can allow power but block programming. If you want, I’ll give exact driver links and install steps. ===

=== - If the external LED blinks but onboard LED doesn't → keep using the board (ignore faulty onboard LED) or reflow the solder if you're comfortable. ===
* If nothing blinks and loopback fails and bootloader reburn fails → board’s USB-serial or MCU is likely dead. Replace the board (cheap clones ~₹300–800, genuine UNO more).
* If you need reliability for projects, buy a genuine UNO or a known-good clone from a reliable seller.

=== 1. Enable verbose upload, upload Blink — watch console for “Done uploading”. ===
# Watch RX/TX LEDs during upload.
# Upload the Serial+LED test sketch and open Serial Monitor.
# Test external LED on pin 13.
# Loopback test.
# Re-burn bootloader (if you have another Arduino).
# Check drivers / try different PC or USB cable.
# Replace board if hardware is faulty.

Tell me what happened when you run step 3 (Serial+LED test) and step 4 (external LED test). Based on that I’ll give the exact next command: e.g., steps to re-burn bootloader, driver links, or solder / replace recommendations.

=== User: avrdude: Version 6.3-20190619 ===
avrdude: Version 6.3-20190619
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "C:\Users\Shreyas\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf"

         Using Port                    : COM6
         Using Programmer              : arduino
         Overriding Baud Rate          : 115200
         AVR Part                      : ATmega328P
         Chip Erase delay              : 9000 us
         PAGEL                         : PD7
         BS2                           : PC2
         RESET disposition             : dedicated
         RETRY pulse                   : SCK
         serial program mode           : yes
         parallel program mode         : yes
         Timeout                       : 200
         StabDelay                     : 100
         CmdexeDelay                   : 25
         SyncLoops                     : 32
         ByteDelay                     : 0
         PollIndex                     : 3
         PollValue                     : 0x53
         Memory Detail                 :

                                  Block Poll               Page                       Polled
           Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW  MaxW   ReadBack
           ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
           eeprom        65    20     4    0 no       1024    4      0  3600  3600 0xff 0xff
           flash         65     6   128    0 yes     32768  128    256  4500  4500 0xff 0xff
           lfuse          0     0     0    0 no          1    0      0  4500  4500 0x00 0x00
           hfuse          0     0     0    0 no          1    0      0  4500  4500 0x00 0x00
           efuse          0     0     0    0 no          1    0      0  4500  4500 0x00 0x00
           lock           0     0     0    0 no          1    0      0  4500  4500 0x00 0x00
           calibration    0     0     0    0 no          1    0      0     0     0 0x00 0x00
           signature      0     0     0    0 no          3    0      0     0     0 0x00 0x00

         Programmer Type : Arduino
         Description     : Arduino
         Hardware Version: 3
         Firmware Version: 4.4
         Vtarget         : 0.3 V
         Varef           : 0.3 V
         Oscillator      : 28.800 kHz
         SCK period      : 3.3 us

avrdude: AVR device initialized and ready to accept instructions

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

avrdude: Device signature = 0x1e950f (probably m328p)
avrdude: reading input file "C:\Users\Shreyas\AppData\Local\arduino\sketches\83E1312430345E2C471538B6F9759EC5/sketch_dec2b.ino.hex"
avrdude: writing flash (924 bytes):

Writing | ################################################## | 100% 0.14s

avrdude: 924 bytes of flash written

avrdude done.  Thank you.

=== Assistant: Great — your verbose log shows upload succeeded avrdude done. ===
Great — your verbose log shows upload succeeded (avrdude done. Thank you.). That means the sketch is on the ATmega328P. The problem now is the MCU isn’t visibly running the blink sketch (built-in LED not blinking). Let’s run very targeted tests (in order) to find whether it’s a hardware fault (onboard LED / trace / MCU) or a runtime issue.

Do each step in order and tell me the result for the first step that changes behavior.

=== This will both blink pin 13 and print messages to Serial so we can tell whether the CPU is running. ===

<syntaxhighlight lang="cpp">void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(9600);
  Serial.println("START_TEST");
}

void loop() {
  digitalWrite(LED_BUILTIN, HIGH);
  Serial.println("HIGH");
  delay(500);
  digitalWrite(LED_BUILTIN, LOW);
  Serial.println("LOW");
  delay(500);
}

</syntaxhighlight>
* Upload it (you already know upload works).
* Immediately open Serial Monitor (Ctrl+Shift+M) and set baud 9600.

Expected:
* You should see lines: START_TEST, then alternating HIGH / LOW every 0.5s.
* The built-in LED should blink at the same time.

If you see Serial output but built-in LED does NOT blink, go to Step 2.
If you see no Serial output even though upload said Done, go to Step 3.

Tell me which of the three outcomes happened.

=== The onboard LED or its resistor/trace is likely dead. ===

Wiring external LED (exact):
* Pin 13 → 220Ω resistor → LED long leg (anode)
* LED short leg (cathode) → GND (If you don’t have 220Ω, use nearest ~200–470Ω)

Upload the same Serial+LED test again.
If the external LED blinks and Serial prints, your board is usable — just the on-board LED is faulty. You can continue using the external LED or replace the board.

If the external LED also does not blink but Serial prints — then pin 13 output path is damaged (rare). Stop and tell me the result.

=== This means the MCU might not be running user code (odd, since flash was written). Try these in order: ===

A) Press the RESET button once immediately after upload finishes
* Immediately after you see avrdude done, press RESET and watch Serial Monitor.
* Do you get START_TEST printed? If yes — auto-reset circuit (DTR capacitor) may be faulty. You can press RESET manually each time or fix circuit.

B) Check RX/TX LEDs behavior during upload
* Watch board LED labeled TX/RX while uploading — do they flash? - If they flash during upload, PC talked to board (we know upload works). - If they never flash, but avrdude still said Done — weird; still continue.

C) Power-check — measure board voltages (use multimeter)
* Measure 5V between 5V pin and GND → should read approx 5.0 V.
* Measure 3.3V if present (optional). If 5V is missing or very low, MCU can't run even though flash was written.

D) Check ATmega328P presence / seating
* If your board uses a removable DIP ATmega328P (IC in a socket), power OFF, gently remove the chip and reseat it (careful about orientation notch).
* If SMD chip (surface mount), visually inspect for cracked solder joints.

E) Try Reset while Serial Monitor is closed then open Serial Monitor after a second — sometimes serial console timing hides output.

Report the results for A–E you tried.

=== 1. Power OFF. Put jumper between TX (pin1) and RX (pin0). ===
# Power ON. Open Serial Monitor at 9600 for COM6.
# Type — you should see your typed text echoed.
# Remove jumper.
* If loopback succeeds → USB-serial is OK. Problem is MCU/firmware/run-time.
* If loopback fails → USB-serial or driver issue — but since upload worked earlier this is unlikely.

=== - Re-burn bootloader (only if MCU isn’t starting; you’ll need another working Arduino as ISP). I can give step-by-step if you want. ===
* Replace board — if external LED doesn’t blink, loopback fails, and reset doesn’t help, board likely has hardware damage (cheap clones fail occasionally). Replacing board is cheapest fix.

=== 1. Serial prints & built-in LED blinks — DONE (works). ===
# Serial prints & built-in LED does not blink — go to Step 2 (external LED).
# No Serial output — try Step 3A (press reset after upload) then Step 3C (measure 5V) and Step 4 (loopback).

Tell me the exact outcome after you run Step 1 (upload Serial+LED test and open Serial Monitor) — copy the first lines you see (or say “no output”), and I’ll tell you the precise next action.

=== User: see my external led is working but there is some problem with serial monitor ===
see my external led is working but there is some problem with serial monitor

=== Assistant: Nice — good progress! ===
Nice — good progress! Since your external LED blinks, the MCU is running fine. That narrows the problem to the Serial Monitor connection. Below is a short, precise checklist (in order) to get Serial Monitor working. Try each step and report the first one that fixes it.

=== - Wrong baud rate in Serial Monitor (must match Serial.begin(...)) ===
* Wrong COM port selected in Arduino IDE
* Serial Monitor or another program is blocking the port
* USB-serial driver problem (CH340 / CP2102 / ATmega16U2)
* You opened Serial Monitor before upload or it's not reconnecting after upload

=== ### ===

Upload this tiny test sketch (you already have working upload):

<syntaxhighlight lang="cpp">void setup() {
  Serial.begin(9600);
  Serial.println("SERIAL_OK");
}

void loop() {
  // nothing
}

</syntaxhighlight>

After upload, open Serial Monitor (Ctrl+Shift+M).
* Set baud at the bottom right to 9600.
* Set No line ending (doesn't matter for this test).

If you see SERIAL_OK → Serial works. If not, continue.

===== Top menu → Tools → Port → select the port that says Arduino Uno (COM6) or the COM number shown in Device Manager. =====
If multiple COMs, choose the one that matches Device Manager.

===== Completely close: =====
* Any other Serial Monitor windows
* VS Code (PlatformIO)
* PuTTY / CoolTerm / Python scripts
* Serial plotter instances

Then re-open Arduino IDE and Serial Monitor. Try again.

===== Sometimes Serial Monitor must be opened after upload so it opens the port. =====
Procedure:
# Upload sketch.
# Wait for Done uploading.
# Then open Serial Monitor (Ctrl+Shift+M).

See if output appears.

===== Sometimes DTR/auto-reset timing fails on clones. Do this: =====
# Upload sketch.
# Open Serial Monitor. (Nothing appears.)
# Press the UNO RESET button once.
# Check Serial Monitor — do you get the printed text?

===== - Serial Monitor baud must equal Serial.begin() value. =====
* Try different baud values (9600, 115200) if your sketch uses different.
* Set line ending to No line ending for testing.

===== 1. Power OFF. Place jumper between TX (pin1) and RX (pin0). =====
# Power ON. Open Serial Monitor on COM6 at 9600.
# Type some characters — if they echo back, the USB-Serial interface & driver are OK.
# Remove jumper.

If loopback works but your sketch prints nothing, the MCU may not be sending serial (but you tried blink+serial earlier). If loopback fails, driver/cable/USB-serial chip problem — go to Step 9.

===== Open Device Manager → Ports (COM & LPT) and look at the Arduino entry. Copy the exact name shown (e.g., Arduino Uno (COM6) or USB-SERIAL CH340 (COM6)) and paste here. =====

If it shows Unknown device or has a yellow icon, you need the driver (see step 9).

===== If Device Manager shows CH340 or CP210x or unknown, reinstall the driver: =====
* For CH340 (common cheap clones): search “CH340 driver” and install the Windows driver, then reboot.
* For CP2102: search “CP2102 driver” and install.

If you want, tell me the exact Device Manager text and I will give the exact driver link and step-by-step install commands/GUI steps.

===== Try PuTTY or Tera Term to open COM6 at 9600: =====
* If PuTTY shows the serial output but Arduino Serial Monitor does not, the IDE is the issue.
* If both fail, it's a driver/port issue.

===== Right-click Arduino IDE → Run as administrator, then open Serial Monitor. =====
Sometimes Windows permission blocks access.

===== - Try a different USB cable (must be data cable). =====
* Try another USB port (rear port on desktop).
* Try the UNO on another PC — if Serial Monitor works there, problem is on your PC.

===== Use Process Explorer (Sysinternals): =====
# Download & run Process Explorer.
# Press Ctrl+F, search for COM6.
# It will show which process has the handle. Kill that process (if safe), then try Serial Monitor again.

I can give the download link and exact clicks if you want.

=== Tell me which of these happened (exactly): ===
* “After step 1 I saw SERIAL_OK in Serial Monitor.”
* “Loopback test echoed characters.”
* “Device Manager shows: USB-SERIAL CH340 (COM6).”
* “PuTTY shows output but Arduino Serial Monitor does not.”
* “Nothing changed.”

Also paste the exact name shown in Device Manager for the COM port (e.g., Arduino Uno (COM6)), and whether the Serial Monitor shows any error message when you try to open it (e.g., “could not open port” or it opens but blank).

I’ll give the exact next command or driver link based on what you tell me.

=== User: Sketch uses 2024 bytes 6% of program storage space. ===
Sketch uses 2024 bytes (6%) of program storage space. Maximum is 32256 bytes.
Global variables use 208 bytes (10%) of dynamic memory, leaving 1840 bytes for local variables. Maximum is 2048 bytes.
"C:\Users\Shreyas\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/bin/avrdude" "-CC:\Users\Shreyas\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf" -v -V -patmega328p -carduino "-PCOM6" -b115200 -D "-Uflash:w:C:\Users\Shreyas\AppData\Local\arduino\sketches\83E1312430345E2C471538B6F9759EC5/sketch_dec2b.ino.hex:i"

avrdude: Version 6.3-20190619
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "C:\Users\Shreyas\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17/etc/avrdude.conf"

         Using Port                    : COM6
         Using Programmer              : arduino
         Overriding Baud Rate          : 115200
avrdude: ser_open(): can't open device "\\.\COM6": Access is denied.

avrdude done.  Thank you.

Failed uploading: uploading error: exit status 1

=== Assistant: Good — you pasted the verbose upload output showing the Access is denied at the seropen stage. ===
Good — you pasted the verbose upload output showing the Access is denied at the ser_open stage. That means Windows is blocking COM6 (still). Below is a concise, exact step-by-step checklist to fix it. Do the steps in order and try uploading after each step that says Try upload now. Tell me the first step that changes the result.

=== 1. Close Serial Monitor (Ctrl+Shift+M) — make sure every IDE window’s Serial Monitor is closed. ===
# Quit Arduino IDE entirely (File → Exit).
# Close other apps that may use serial: VS Code, Python scripts, PuTTY, CoolTerm, PlatformIO, serial plotter, etc.
# Re-open Arduino IDE. → Try upload now.

=== Right-click the Arduino IDE icon → Run as administrator → open sketch → Tools → Port → select COM6 → Upload. ===
→ Try upload now.

=== 1. Unplug UNO. Wait 5 seconds. ===
# Plug it into a different physical USB port (prefer rear USB on desktop).
# Use a different USB data cable (not phone/charge-only cable).
# Watch Device Manager → Ports (COM & LPT). Note the COM number that appears (it may change). Select that port in Arduino IDE. → Try upload now.

=== If COM6 stays locked, change the port number Windows uses: ===
# Open Device Manager → Ports (COM & LPT).
# Right-click the Arduino device (e.g., Arduino Uno (COM6) or USB-SERIAL CH340 (COM6)) → Properties.
# Tab Port Settings → click Advanced....
# Under COM Port Number choose an unused port (e.g., COM3 or COM4). Click OK → Close.
# In Arduino IDE Tools → Port, select the new COM. → Try upload now.

=== If COM6 is still denied, some program holds it. Use Process Explorer from Microsoft Sysinternals: ===
# Download Process Explorer from Microsoft Sysinternals (search “Process Explorer Sysinternals” — it’s from Microsoft).
# Run procexp.exe as Administrator.
# Press Ctrl+F (Find Handle or DLL). In the search box type COM6 and press Enter.
# If a result appears, note the process name. Select the process in Process Explorer, right-click → Kill Process (only if you recognize it and it's safe to kill).
# Close Process Explorer, re-open Arduino IDE and upload. → Try upload now.

If you cannot run Process Explorer, you can use Windows Resource Monitor: Start → type resmon → CPU → Associated Handles → search COM6.

=== If you prefer command line and are comfortable in an elevated command prompt: ===
# Download handle.exe from Sysinternals.
# Open Command Prompt as Administrator and run:

<syntaxhighlight>handle.exe -a COM6

</syntaxhighlight>
# The output will show PIDs that have handles on COM6. Kill them in Task Manager (right-click → End task).

→ Try upload now.

=== 1. Device Manager → Ports (COM & LPT) → right-click the Arduino device → Uninstall device. ===
# If offered, check “Delete the driver software for this device” and confirm.
# Unplug Arduino. Wait 5s. Plug it back in. Windows will reinstall the driver.
# Select the new COM in Arduino IDE → Upload.

If Device Manager shows USB-SERIAL CH340 or CP210x, install the vendor driver for that chip (CH340 or CP2102). If you want I’ll give exact driver links and install steps — tell me which device name you see in Device Manager.

=== 1. Power OFF board. Put a jumper between RX (pin0) and TX (pin1). ===
# Power ON the board. Open Serial Monitor (select the COM shown) at 9600.
# Type text — if it echoes back, the USB-serial interface/driver is OK. Remove jumper after test. If loopback fails, the USB-serial or driver is the issue.

=== Some antivirus or background utilities can lock serial ports. Temporarily disable antivirus or serial-related utilities and try upload. (Re-enable after test.) ===

=== If all else fails, plug the UNO into another computer with Arduino IDE and try upload. If it works there, the problem is specific to your Windows machine (drivers / background process). ===

===== After you try the steps above, tell me exactly one of these (don’t guess): =====
* “Step X fixed it — uploads now succeed” (say which step number)
* “Process Explorer showed process_name.exe using COM6” (paste the name)
* “Device Manager shows: __________ (COM6)” (copy the exact string shown)
* “Loopback test: [worked / failed]”
* “Still same Access is denied after all steps”

Tell me that and I’ll give the targeted next command (driver link, how to kill a specific process, or re-burn bootloader instructions if needed).

=== User: 26.2109 ===
26.2109

=== Assistant: Alright — you’ve been hunting the right chip and ended up with a bunch of markings AMS1117 / ATmega.... ===
Alright — you’ve been hunting the right chip and ended up with a bunch of markings (AMS1117 / ATmega...). No worries — we’ll finish this. Since the USB-side chip text wasn’t clear, I’ll give you a no-nonsense plan with three paths (fast fixes, diagnostic checks, permanent fixes). Pick whichever you want to try first — I’ll assume you want to fix it on this PC.

=== A. Try the easiest software fixes first (drivers, alternate terminal) — low effort, often fixes clones. ===
B. Run a loopback + Device Manager check (confirm whether USB-serial is healthy).
C. Bypass the broken USB chip with an external USB-TTL/FTDI adapter (guaranteed working workaround).

If you say “do A” I’ll give those exact steps. If you say “do B” or “do C” I’ll give the exact commands/wiring and links. If you want, I’ll give all three now — below are all steps so you can run whichever.

=== 1. In Device Manager (Windows): open Ports (COM & LPT) and USB controllers. - Copy exactly what the Arduino entry is named (paste it here). - If it shows CH340, CP210x, Prolific, or USB Serial, install that driver (see links below). ===
# Download & install common drivers (one of these will match most clones): - CH340 (very common cheap clones) — search “CH340 driver Windows” or use the site from the manufacturer of CH340. - CP210x (Silicon Labs) — search “CP210x VCP driver”. - FTDI (rare on clones) — “FTDI VCP driver”. (If you want, I’ll paste direct download links for the driver that matches the name you see in Device Manager.)
# After installing driver: unplug board → plug into a rear USB port → wait a few seconds → note COM number → in Arduino IDE choose Tools → Port → that COM.
# Upload a test sketch and then open Serial Monitor after upload. Set baud to 9600.

If this fixes Serial Monitor, done. If not, move to B.

=== 1. Loopback test (quick): - Power OFF board. Put a jumper from TX (pin1) → RX (pin0). - Power ON. Open Device Manager and note the COM port (e.g., COM6). - Open PuTTY or Arduino Serial Monitor on that COM at 9600. Type some letters — if they echo back, the USB-serial chip and driver are OK. Remove jumper afterwards. - If echo works but Serial Monitor still doesn’t show your sketch output, the MCU is not sending serial (but you said MCU runs so unlikely). ===
# If loopback fails → the USB-serial chip or its driver is faulty. Continue to C or use Process Explorer to see if another process locks COM.
# Process Explorer check (if you get “Access is denied”): - Download Process Explorer (Sysinternals). Run as admin → Ctrl+F → search COM6 → kill process that holds it (if safe).
# Try alternate terminal: Install PuTTY or Tera Term. Try opening COM port there. If PuTTY can open and show, Arduino IDE issue; if not, driver/hardware issue.

Tell me results: “loopback OK / loopback FAIL / Process Explorer shows X.exe” and I’ll continue.

=== If device manager is unclear or loopback fails, the fastest reliable fix is to use an external USB-TTL adapter (FTDI / CP2102 / CH340 based modules). This bypasses the board’s USB chip entirely. ===

Exact wiring (5V UNO):
* USB-TTL TX → UNO RX (pin 0)
* USB-TTL RX → UNO TX (pin 1)
* USB-TTL GND → UNO GND
* USB-TTL 5V → UNO 5V (only if you want the adapter to power the board)
* USB-TTL DTR → UNO RESET (optional — for auto-reset; otherwise press RESET before upload)

Then in Arduino IDE choose the correct COM for the USB-TTL adapter and upload normally. This will always work if the ATmega328P is fine (your external LED shows it is).

Buy one: small USB-TTL modules cost around ₹150–₹400. Search: “USB to TTL adapter FTDI CP2102 CH340” on Amazon/Flipkart.

=== If Device Manager shows an ATmega16U2 device or unknown device (and you identify the small chip as ATMEGA16U2), repairing requires reflashing the 16U2 with DFU tools. I can give step-by-step if you want to try reflashing — but for most users it’s faster to use the external USB-TTL adapter or buy a new board. ===

=== Paste one of these exact results so I know the next step: ===
# The exact Device Manager name for the Arduino port (copy/paste the string under Ports).
# Result of loopback test: “echoed” or “no echo”.
# If you want to go straight to workaround: type “Use adapter” and I’ll give wiring + where to buy.

Pick one and paste it — I’ll give the exact next commands and links.