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Initial flashing using AVR ISP programmer


(Alexander) #1

Hello, folks. I have a question regarding the initial flashing of the Blue ESC, done using an AVR ISP programmer, before the bootloader is installed. In particular, I want to make sure I’m wiring the programmer to the processor correctly during this procedureto avoid letting out the smoke:

Processor pin 15 (MOSI) <-> programmer pin MOSI

Processor pin 16 (MISO) <-> programer pin MISO

Processor pin 17 (SCK) <-> programmer pin SCK

Processor pin 4, 6 (VCC) <-> programmer pin VCC

Processor pin 3, 21 (GND) <-> programmer pin GND

Should the processor be powered from the programmer, or the local 5V supply (with the programmer and processor grounds connected)? Without a “special tool” for contacting the pins, what’s the safest way to access the MISO and MOSI pins - temporarily solder a fine wire?

Cheers & thank you in advance, -Alex


(Rusty) #2

Alex,

The connections look good. I would strongly recommend powering the ESC from a different source and not through the programming. Most programmers aren’t designed to handle much power output.

You can solder a fine wire to access the pins, but I would recommend a proper tool. HobbyKing has an excellent one (http://www.hobbyking.com/hobbyking/store/__27195__Atmel_Atmega_Socket_Firmware_Flashing_Tool.html). Note that you’ll need a programmer with a 10-pin programming port to use it.

Good luck!

-Rusty


(Alexander) #3

Rusty, thanks again for the quick reply. When I say “powered from the programmer”, I mean during the flashing procedure only - I would expect that a device intended for programming a processor would at least have enough juice to power that processor.

The socket flashing tool is really cool - thank you for the link!

Cheers, -Alex


(Rusty) #4

Alex,

Yes, I know what you meant, but if anything goes wrong, like a MOSFET shorting power after it is programmed, you could fry the programmer.

Best,

Rusty


(Alexander) #5

Rusty, gotcha - I hadn’t considered that option. So, I’ll generate the +5 Vcc locally on the ESC by powering the battery bus, leave the programmer <-> Vcc disconnected, and ties the programmer and ESC grounds together.

Cheers, -Alex