Bootloader won't work! Pro Mini clone

Other Hardware Hardware Development
1

HI, this is a simple case of a new board, amtel 328, nothing clever, there is a 'serial port' the same as the pro mini (16mhz clock 5v version). I can program the board via 'unpload using a programmer' from arduino ide 2.1.1, (Atmel ICE)

I have tested the serial interface and can send and recieve data over the serial interface (tx/rx pins on the 328) I know the DTR is wired correctlky and triggers a reset of the 328 when grounded.

attemps to burn a bootloader from arduino IDE fail with an error:
avrdude: verification error, first mismatch at byte 0x0000
0xff != 0x0f
avrdude: verification error; content mismatch

I can however burn and verify the bootloader using Atmel studio, then setting the fuses to : ext 0xFD, high 0xDE, low 0xFF, I have seen others have 0x05 for extended, but with atmel studio 5 this cannot be set. So BOD=2v7

Now if I try and program via the serial interface from the Arduino IDE I get an error- port cannot be opened. even if I power off/on the system I get the same error

Help please!

Thanks Ian

I have burned the optiboot_atmel328.hex bootloader via

2

On the promini there is a capacitor between the DTR line and the reset pin. This causes a short negative pulse on the reset pin even when the DTR line is kept low. Does your board also have that capacitor?

You can test by uploading a blink sketch and if then you tie the reset pin to GND it will be kept in reset. If you tie the DTR pin to GND it will reset once and then blink on.

3

Hi,

Yes, it does 100nf between the DTR pin and the reset line of the 328

Ta Ian

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