Bootload ATmega328p with USB serial interface

For better or worse my company has been experimenting with some customized PCB layouts for device prototypes. We have a device we've constructed and our 1st 5 custom PCBs have turned out very nice. But we have encountered a problem we overlooked in planning. we don't have headers accessible to burn a boot-loader to our chip.

We've been looking around for some information on how we could burn the boot-loader to these prototypes over using the access granted to us via the ATmega16u2 chip.

We can successfully flash the 16u2 with the Arduino Uno loader and we can reset it to DFU mode etc..

Long term we can order our ATmega328p(s) with the boot-loader already loaded. We just wanted to expend all options before ordering new prototypes with the boot-loader preinstalled.

Any insight or information is greatly appreciated.

(I attached some images of the device.)

Raw ATmega328P is programmable via parallel or ISP. Do not think about parallel programming at all. For ISP programming, the ISP pins must be available so everything depends on what is connected there. It is not clear from this picture anything, at least for me. Schematics would be better.
Time ago, I saw here on forum photo of some connector (I think from Mr. CrossRoads) for TQFP 32 package which allows touch with IC legs but MISO, MOSI, SCK and RESET have to be available (not grounded, connected to VCC or low impedance...).

Here is: Terapeak

Thanks for the response.

The schematic is pretty much the same as the standard UNO R3 but we removed a lot of the headers to shrink down our design’s size, albeit without thinking through the consequences.

Our experience with Arduino Uno R3 development never got to the point where we needed to flash any bootloaders or custom firmware. It was all just sketches.

The chips used in the board are:

  • ATMEGA328P-AUR
  • ATMEGA16U2-MUR

As I said we can access the 16u2, will that adapter cable you linked work on the 328p-AUR?

Thanks again for the assistance!

ARDUINO_UNO_INTERFACE_09_JAN_17.pdf (52.9 KB)

ASSY-BOT.pdf (12 KB)

ASSY-TOP.pdf (12.3 KB)

It have to work with any TQFP32 package so YES for ATmega328p-AUR. As I see from the schematics, you have all ISP pins connected just to header. It have to work.

Our experience with Arduino Uno R3 development never got to the point where we needed to flash any bootloaders or custom firmware. It was all just sketches.

Heh, I know this feeling. You are not the first nor the last.

EDIT: Forgot to mention, it is just connector/reduction. The ISP programmer is needed. The UNO can do this job. However, if you will use ISP programmer more frequently I am recommending to
buy USBasp programmer from ebay which is very handy and exactly would fit to the 10 pin connector on the other side. See the description:
http://www.ebay.com/itm/Atmel-Atmega-AVR-TQFP32-Socket-Solderless-Firmware-Flash-Programming-Tools-/322291851017