I have two Arduino Uno boards that I've been playing with a virtual wire transmitter and receiver. the transmitter uses the TX pin and receiver uses RX, so I've needed to disconnect them to upload the sketches. I recently forgot to disconnect the receiver and the upload failed as expected, but no I can't load anything on the board. I get the error:
avrdude: verification error, first mismatch at byte 0x0000
0x0c != 0x62
avrdude: verification error; content mismatch
I've tried both boards with the same setup, proper board selected, proper USB connection, the lights light, it blinks away, and one works, the other gives the error message.
I thought perhaps I'd corrupted the bootloader, so I tried rewriting it, but I get avrdude: usbdev_open(): did not find any USB device "usb"
Is there some kind of protective device that needs to be reset? Or is this puppy toast.
To rewrite the bootloader you need a programmer, and use a cable to the ICSP header.
I use the USBasp programmer with an adapter from a 10-pin to a 6-pin header.
If avrdude can't open the device, it can't see the programmer, you have to fix that first.
Ah, I see, I did some more reading, I can see this is going to be a long trip. Is there a specific USBasp programmer you recommend--there seems to be a lot of them at radically different prices.
I also used Nick Gammons chip fuse detector to look at my unresponsive arduino uno. I think what I got means my bootloader is AWOL. This is what I got:
Atmega chip detector.
Entered programming mode OK.
Signature = 1E 95 0F
Processor = ATmega328P
Flash memory size = 32768
LFuse = FF
HFuse = D6
EFuse = FD
Lock byte = C0
Clock calibration = 98
Bootloader in use: Yes
EEPROM preserved through erase: Yes
Watchdog timer always on: No
Bootloader is 512 bytes starting at 7E00
I bought the cheapest USBasp programmer on Ebay.
Well, actually I have two of those cheapest, since one of them has timing problems on the USB to my computer.
If you mention something, like the fuse detector, please add a link to it (just copy the url in the text).
If you use another Arduino board to test that, you can use the other Arduino also as a programmer.
Reading 0xFF could be that the value is 0xFF or it could be that nothing could be read.