Re: [avrdude-dev] ATmega stopped responding when fuses set to crystal

[Wayne Contello]

Low set to 0xED and Hi set to 0x99

do NOT look correct to me.  

Lo Fuse = 0xED
CKDIV8 = 1 (not programmed)
CKOUT = 1 (not programmed)
CKSEL = 1101            ?


HiFuse = 0x99
RSTDISBL = 1 (not programmed)
DWEN = 0 (programmed)… so this means you enabled Debug wire
SPIEN = 1 (not programmed)… so this means that SPI programmed is disabled
WDTON = 0 (programmed) so the watchdog is enabled (and probably resetting all 
the time)

Try using the debug wire interface of avrdude to restore SPI programming 
(remember, the bits are inverted in fuse flash locations).



I used a 16MHz OSC and se up the fuses like this using the terminal mode of 
avrdude:
avr-objdump -D -s -t main.elf
 >>> read lfuse
 0000  ae                                                |.               |
  avrdude> read hfuse
 >>> read hfuse
 0000  df                                                |.               |

 
 write lfuse 0 0xae
 write hfuse 0 0xdf



———————————————————————————
Wayne Contello
10004 Palmbrook Drive
Austin, Texas 78717

512-653-0851
address@hidden
———————————————————————————

> On Jul 9, 2016, at 2:35 AM, Rick Mann <address@hidden> wrote:
> 
> I finally got my ATmega16m1 responding to avrdude/avrisp mkii, with the 
> default fuses.
> 
> I added an 8 MHz ceramic resonator to the board, and programmed these fuses: 
> low: 0xED, hight 0x99
> 
> Now it won't respond to avrdude:
> 
> avrdude: stk500v2_command(): command failed
> avrdude: stk500v2_program_enable(): bad AVRISPmkII connection status: Unknown 
> status 0x00
> avrdude: initialization failed, rc=-1
> 
> Poking at it with an oscilloscope, I see a nice 8 MHz sinusoid on the 
> resonator pins. The SCK and MOSI burst nice clean square waves. MISO seems to 
> just go high, but not quite all the way. Looks like one high pulse to 2.5 V.
> 
> OH! I just noticed. Reset looks good until I try to communicate. Then it 
> turns to shit, even after the transaction is done. Then it has a dirty square 
> wave of about 1.8 kHz, and it's coming from the AVRISP MkII.
> 
> Everything else looks good. Power's steady.
> 
> Any idea what might be wrong? Thanks.
> 
> -- 
> Rick Mann
> address@hidden
> 
> 
> 
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