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Update JTAG EEPROM write troubleshooting

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stefanrueger
2025-10-22 12:56:22 +02:00
parent 12a16d64c9
commit b1d2f19ac1
1 changed files with 12 additions and 13 deletions
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src/doc/avrdude.texi
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@@ -5289,22 +5289,21 @@ If you know how to work around this on your OS, please let us know.
@cindex @code{eeprom}
@item
Problem: Page-mode programming the EEPROM (using the -U option) does
Problem: Page-mode programming the EEPROM using the -U option does
not erase EEPROM cells before writing, and thus cannot necessarily overwrite
previous values that are different to 0xff.
non-0xff values.
Solution: None. This is an inherent feature of the way JTAG EEPROM
programming works, and is documented that way in the Atmel AVR
datasheets.
In order to successfully program the EEPROM that way, a prior chip
erase (with the EESAVE fuse unprogrammed) is required.
This also applies to the STK500 and STK600 in high-voltage programming mode.
Solution: This is an inherent feature of how JTAG EEPROM programming
works, and is documented as such in the datasheets. In order to
successfully program the EEPROM, a prior chip erase with the EESAVE fuse
unprogrammed is required. This also applies to the STK500 and STK600 in
high-voltage programming mode.
Programming the EEPROM in the terminal, however, will recognise that the
programmer struggles to write to EEPROM and read the flash, EEPROM and, if
present, bootrow contents, perform a chip erase and then write the
memories back. This happens when flushing the cache or leaving the
terminal and, out of necessity, take some time.
The terminal, however, recognises that the programmer struggles to write
to EEPROM. It then reads flash, EEPROM and, if present, bootrow contents,
performs a chip erase and then writes these memories back. This happens
when flushing the cache or leaving the terminal and takes some time.
EESAVE needs to be unprogrammed for this.
@item
Problem: How do I turn off the @var{DWEN} fuse?