Wrong device signature

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1

I have two ATtiny84's which I want to program with an empty sketch using my Arduino Uno running ArduinoISP and DrAzzy's ATTinyCore. For one, it works perfectly fine, but for the other one I get following error:

Arduino: 1.8.12 (Linux), Board: "ATtiny24/44/84, Enabled, ATtiny84, 8 MHz (internal), EEPROM retained, B.O.D. Disabled, Clockwise (like damellis core), Enabled, Port A (CW:0~7,CCW:3~10)"

Sketch uses 302 bytes (3%) of program storage space. Maximum is 8192 bytes.
Global variables use 9 bytes (1%) of dynamic memory, leaving 503 bytes for local variables. Maximum is 512 bytes.
/home/kurt/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/bin/avrdude -C/home/kurt/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/etc/avrdude.conf -v -pattiny84 -cstk500v1 -P/dev/ttyACM0 -b19200 -Uflash:w:/tmp/arduino_build_388222/tiny84_serial.ino.hex:i 

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 "/home/kurt/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/etc/avrdude.conf"
         User configuration file is "/home/kurt/.avrduderc"
         User configuration file does not exist or is not a regular file, skipping

         Using Port                    : /dev/ttyACM0
         Using Programmer              : stk500v1
         Overriding Baud Rate          : 19200
         AVR Part                      : ATtiny84
         Chip Erase delay              : 4500 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     6     4    0 no        512    4      0  4000  4500 0xff 0xff
           flash         65     6    32    0 yes      8192   64    128  4500  4500 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

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

avrdude: Device signature = 0x1e0f00
avrdude: Expected signature for ATtiny84 is 1E 93 0C
         Double check chip, or use -F to override this check.

avrdude done.  Thank you.

Since it's working fine, for one of my chips, wiring and setup should be correct. I found a few threads with similar problems, but they all had device signature 0x000000 and in the end they found out they had wiring problems. Since I get a non-zero device signature, I guess the problem is something else. Does anyone have a clue?

Thanks in advance!

2

Do you get the same signature every time when you try to upload code or do you get different signature ? Could you attach a clear photo of the defected ic ?

3

Now there's an exotic issue! Always the same sig or different?

The fact that the first byte is right, but the rest are not is pretty weird...

And yeah, that would be the first thing I would look at. Also, recheck wiring again - loose connection/etc? Ohm out all the connections...

4

Yes, it was always the same signature. I tried adding a 10uF capacitor to the Uno between Reset an GND, as suggested by some tutorials, then it worked.. Very strange. I programmed many ICs and never needed this capacitor.

5

Check if there is any change in the part numbers. Or use the avrdudess to detect the ic automatically.

6

I have a mega328p on a clone OpenLog board that does something very similar. All the wiring checks out.

You don't say if your Tiny84s were brand new blank devices or if they have bootloaders already installed.

I'm not entirely sure, and this is where somebody with more experience of fuse bits may know, but if the device has the SPIEN fuse programmed, then is the ISP hardware inside the chip completely disabled? If so, I wonder if the ability to read the chip signature is also disabled and the programmer is interpreting random voltage levels as a signature. Doesn't really explain why the programmer consistently give the same wrong signature.

7

KrawallKurt:
Yes, it was always the same signature. I tried adding a 10uF capacitor to the Uno between Reset an GND, as suggested by some tutorials, then it worked.. Very strange. I programmed many ICs and never needed this capacitor.

Wacky! If this fixed it though, it implies that the Uno was resetting partway through the process of reading the signature. Strange indeed!

8

If the UNO is powered from a USB port straight from a PC or notebook (not from a self-powered hub), then the available USB current could be limited. If the fuse settings on the ATtiny84's are different, then the current demand might be slightly different.

Yeah, lots of if's - just thinking out loud, but I would see if using a powered hub could be a preferred solution.