uploading code to bluno
Kenneth.Swinney 2026-09-08 23:58:50 163 Views6 Replies I ordered a Bluno a couple of years age and am just now trying to use it.
I am trying to control the Bluno with the Bluetooth for Arduino app on my iphone.
The app is able to find the Bluno and connect.
I was able to load the sample code to send from serial monitor to the iphone and it worked.
However, when I changed the code and tried to upload again, it gives the error message
I have tried disconnecting and turning every thing off, but same response.
Any suggestions on what to try next are welcome.
You can give my method a try.
In your iPhone Settings > Bluetooth, find the Bluno and tap "Forget This Device" (or toggle Bluetooth off entirely).
Plug Bluno into USB. Make sure the LINK LED is OFF.
In Arduino IDE, select Tools > Board > Arduino Uno and the correct COM port.
Click Upload.
After the sketch is uploaded, you can re-pair the iPhone and use the app normally.
Jason.Miao I tried this but no change.
The Link LED on the BLUNO stays on (red) and the pair led is on (green)
Bluetooth on computer and phone is off.
the arduino IDE recognizes the board as Arduino uno, but will not load a sketch.
IT responded to the AT command with “Enter AT command”
I fear there may be something wrong with the Bluno.
thanks for the help.
If the LINK LED is still on after forgetting the iPhone device, something else is keeping the BLE connection alive. "Computer Bluetooth on, phone off" means your PC might be the one auto-reconnecting — Windows and macOS do this silently for paired BLE devices.The fact that AT commands respond and the IDE sees the board means the hardware is fine — it's just the CC2540 refusing to let go of the UART. The AT restart usually fixes it.
note that the bluno is connected to computer via usb.
Kenneth.Swinney Thank you for your reply.
My earlier comment has an error. the bluetooth on my windows computer is OFF.
I agree that the bluno is connecting to something, or at least acts like it is.
I get no response to AT+RESTART or AT+RESET or AT+SETTING=DEFAULT
I think it should respond with an “OK”
If I hold the reset down for 5 sec, it seems to restart but the green paired led slowly comes back on.
Any other ideas would be appreciated
the Bluetooth-off detail actually helps narrow it down.
The green pairing LED slowly coming back on after a reset tells me the module isn't releasing the link to the old paired device. The CC2540 keeps trying to reconnect to whatever it bonded with last, so it holds the UART busy — which is exactly why the upload fails with "programmer is not responding" and why it can't stay idle. On Bluno the LINK LED needs to be OFF before you upload, because while it's on the BLE occupies the serial port (Bluno example docs call this out explicitly).
Since AT commands now go silent (they did answer earlier), the module looks stuck in that reconnect loop. The clean, documented way to clear a stale connection + pairing is to reflash the BLE firmware from boot mode:
Fully power off (unplug USB, turn off any nearby BT devices), wait ~30s.
Put the Bluno in boot mode: press and hold the BOOT button, plug in USB, and keep holding until the two LEDs blink alternately, then release.
Download the firmware from the Document/Support section and load SBL_BlunoV*.bin for Bluno (Update BLE Firmware on Bluno).
When done, the LINK LED should be OFF — that's your green light. Select Tools > Board > Arduino Uno, pick the correct COM port, and upload.
Only after the sketch uploads successfully, re-pair the iPhone app.
On the AT "OK" point: not every command returns OK, and no reply usually means the running sketch has taken over the serial instead of forwarding to the BLE module, so the CC2540 never hears them. Reprogramming the AVR (step 4) restores AT behavior — then AT+SETTING=DEFAULT doubles as a factory reset that also clears pairing.
If the firmware reflash doesn't help either, that points to the module side and DFRobot support would be the next step.
Hope this helps!
