Reading and Writing Fuses with avrdude

[craigfoo]

Thanks for this wonderful project! I'm working with an ATTiny816 and I can successfully flash with avrdude. I tried to read the current fuse settings and I guess there isn't a configuration in order to do so? This is the message I get after running the command below:

"lfuse" memory type not defined for part "ATtiny816"

Command:
avrdude -c jtag2updi -P com15 -p t816 -U lfuse:r:-:i -v

Output:

avrdude: Version 6.3, compiled on Feb 17 2016 at 09:25:53
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "C:\WinAVR-20100110\bin\avrdude.conf"

         Using Port                    : com15
         Using Programmer              : jtag2updi
JTAG ICE mkII sign-on message:
Communications protocol version: 1
M_MCU:
  boot-loader FW version:        1
  firmware version:              6.00
  hardware version:              1
S_MCU:
  boot-loader FW version:        1
  firmware version:              6.00
  hardware version:              1
Serial number:                   00:00:00:00:00:00
Device ID:                       JTAGICE mkII
         AVR Part                      : ATtiny816
         Chip Erase delay              : 0 us
         PAGEL                         : P00
         BS2                           : P00
         RESET disposition             : dedicated
         RETRY pulse                   : SCK
         serial program mode           : yes
         parallel program mode         : yes
         Timeout                       : 0
         StabDelay                     : 0
         CmdexeDelay                   : 0
         SyncLoops                     : 0
         ByteDelay                     : 0
         PollIndex                     : 0
         PollValue                     : 0x00
         Memory Detail                 :

                                  Block Poll               Page                       Polled
           Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW  MaxW   ReadBack
           ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
           signature      0     0     0    0 no          3    0      0     0     0 0x00 0x00
           prodsig        0     0     0    0 no         61   61      0     0     0 0x00 0x00
           fuses          0     0     0    0 no          9    0      0     0     0 0x00 0x00
           fuse0          0     0     0    0 no          1    0      0     0     0 0x00 0x00
           fuse1          0     0     0    0 no          1    0      0     0     0 0x00 0x00
           fuse2          0     0     0    0 no          1    0      0     0     0 0x00 0x00
           fuse4          0     0     0    0 no          1    0      0     0     0 0x00 0x00
           fuse5          0     0     0    0 no          1    0      0     0     0 0x00 0x00
           fuse6          0     0     0    0 no          1    0      0     0     0 0x00 0x00
           fuse7          0     0     0    0 no          1    0      0     0     0 0x00 0x00
           fuse8          0     0     0    0 no          1    0      0     0     0 0x00 0x00
           lock           0     0     0    0 no          1    0      0     0     0 0x00 0x00
           data           0     0     0    0 no          0    0      0     0     0 0x00 0x00
           usersig        0     0     0    0 no         32   32      0     0     0 0x00 0x00
           flash          0     0     0    0 no       8192   64      0     0     0 0x00 0x00
           eeprom         0     0     0    0 no        128   32      0     0     0 0x00 0x00

         Programmer Type : JTAGMKII_PDI
         Description     : JTAGv2 to UPDI bridge
         M_MCU hardware version: 1
         M_MCU firmware version: 6.00
         S_MCU hardware version: 1
         S_MCU firmware version: 6.00
         Serial number:          00:00:00:00:00:00
         Vtarget         : 5.0 V

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.08s

avrdude: Device signature = 0x1e9321 (probably t816)
avrdude: NOTE: Programmer supports page erase for Xmega devices.
         Each page will be erased before programming it, but no chip erase is performed.
         To disable page erases, specify the -D option; for a chip-erase, use the -e option.
"lfuse" memory type not defined for part "ATtiny816"

avrdude done.  Thank you.

I'm also using PlatformIO for development and I want to confirm that using the fuse settings in the .ini file will be part of the my final hex file that I can flash using avrdude. I'm wondering if I can flash the chip one with a single .hex file that would include the fuse settings AND app code. Am I understanding correctly?

platform.ini

board_hardware.oscillator = internal
board_hardware.bod = 2.7v
board_hardware.eesave = yes
board_hardware.updipin = updi

[SpenceKonde]

I have no idea how fuses are set on pio - I've never used it; @MCUdude wrote the platformio doc and was instrumental in making that available.

AFAIK fuses are never part of the hex file, at least not for non-microchip tooling (I think Microchip official tools have some way that they embed the fuses in a hex file, we don't do that).. Fuses are set with -Ufusen (where n is a 0 through 8) when uploading or bootloading (again, I don't know how much of this is carried over to platform IO)

You can read out the fuses with something like:

/path/to/avrdude -C/path/to/avrdude.conf -pt816 -cjtag2updi -PCOM15 -b115200 -Ufuses:r:output.hex:i

Will generate something like:

:09000000000002FF00C50400002D
:00000001FF

First 4 bytes are length, address start h, adddress start l, record type, then the next 9 bytes are fuse values, in order, followed by the checksum byte, so that comes out to:

junk: :09000000
fuse0: 00
fuse1: 00
fuse2: 02
fuse3: FF
fuse4: 00
fuse5: C5
fuse6: 04
fuse7: 00
fuse8: 00
junk: 2D
more junk: :00000001FF

[jazzjohn27]

For an ATtiny202, this command line
avrdude.exe -p t202 -c serialupdi -P com5 -U fuses:r:.\fuseFile.hex:i
Reading fuses memory ...
Writing 10 bytes to output file fuseFile.hex_

yields this in a fuseFile.hex :
:0A000000000001FF00C5040000FF2E
:00000001FF

Going by your breakdown, I parsed it like this:

:0A000000
00 WDT
00 BOD
01 OSC
FF reserved
00 reserved
C5 SYSCFG0
04 SYSCFG1
00 APPEND
00 BOOTEND
FF reserved
2E LOCKBIT
:00000001FF

Question: If I want to change a bit in one of the registers, what do I write back? Just the registers or keep the "junk" and figure out the new checksum?

Update: Figured it out. Can write to just one register at a time as long as the hex file format is adhered to. If the checksum is wrong, avrdude will display the correct one to use.