How to program attiny85 on a digispark USB board without using USB

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1

I have code written for attiny85 digispark boards and I have been able to program them successfully using the USB micronucleus method with Arduino IDE 1.8.19.

What I want to do now is program the same code using AVR ISP method, and blow away the bootloader. Reason is that I want the program to run when first powered up, not after seconds (10?) of the bootloader running looking to see if I want to program the chip again.

I've read that I can use the AVR ISP method, so I programmed an Arduino Nano and wired it up to the Digispark. Problem is that I cannot get the Arduino IDE to allow me to program the Digispark using the AVR ISP method, even though I've chosen it. Whenever I try to upload to the device, I get a prompt to "Please plug in the device (will time out in 60 seconds)".

Reading other posts, some folks have used the Adafruit Trinket as the device instead of Digispark. Problem is my code uses the DigiKeyboard library for button checking. I could change the code but would rather just figure out how to program a Digispark, as an attiny85, using the AVR ISP method.

What am I missing that I cannot get the AVR ISP mode to work?
Here's a screenshot showing that I am choosing the programmer as AVR ISP.

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2

Are you using "upload Using Programmer"?

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1 Like
3

This is embarrassing - I didn't realize that was even there.

That was what I needed. Thanks! Now to figure out what this error is - wiring looks correct.

avrdude: Version 6.3-20190619
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "C:\Users\xxxx\AppData\Local\Arduino15\packages\digistump\hardware\avr\1.7.5/avrdude.conf"

         Using Port                    : COM8
         Using Programmer              : stk500v1
         Overriding Baud Rate          : 19200
         AVR Part                      : ATtiny85
         Chip Erase delay              : 400000 us
         PAGEL                         : P00
         BS2                           : P00
         RESET disposition             : possible i/o
         RETRY pulse                   : SCK
         serial program mode           : yes
         parallel program mode         : yes
         Timeout                       : 200
         StabDelay                     : 100
         CmdexeDelay                   : 25
         SyncLoops                     : 32
         ByteDelay                     : 0
         PollIndex                     : 3
         PollValue                     : 0x53
         Memory Detail                 :

                                  Block Poll               Page                       Polled
           Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW  MaxW   ReadBack
           ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
           eeprom        65    12     4    0 no        512    4      0  4000  4500 0xff 0xff
           flash         65     6    32    0 yes      8192   64    128 30000 30000 0xff 0xff
           signature      0     0     0    0 no          3    0      0     0     0 0x00 0x00
           lock           0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           lfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           hfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           efuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
           calibration    0     0     0    0 no          1    0      0     0     0 0x00 0x00

         Programmer Type : STK500
         Description     : Atmel STK500 Version 1.x firmware
         Hardware Version: 2
         Firmware Version: 1.18
         Topcard         : Unknown
         Vtarget         : 0.0 V
         Varef           : 0.0 V
         Oscillator      : Off
         SCK period      : 0.1 us

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.02s

avrdude: Device signature = 0x000000 (retrying)

Reading | ################################################## | 100% 0.02s

avrdude: Device signature = 0x000000 (retrying)

An error occurred while uploading the sketch
Reading | ################################################## | 100% 0.02s

avrdude: Device signature = 0x000000
avrdude: Yikes!  Invalid device signature.
         Double check connections and try again, or use -F to override
         this check.


avrdude done.  Thank you.
4

Hi @AlpineJoe. You should double check all your wiring. The "Device signature = 0x000000" happens when there is no communication at all between the programmer and the target board.

5

Wiring looks correct, verified it a few times. I am hooking up to the P0 - P5 pads on the Digispark board and not to the bare chip. Maybe one of the signals is shared with something else on the board and goofing up communications.

6

Maybe if you power it via its usb connector, by plugging it in a pc the USB conflicts. I use to power them from the Arduino directly, to be sure only the required connections are made.

7

Solved - I tied the attiny85 reset to the Nano reset instead of pin 10. Once I corrected that, the nano programmed with the AVR ISP programmed the attiny85 on the Digispark board.

Really appreciate all the help!

8

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