Fix PICKit2 ATmega2560 flash paged flash read #1023
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The paged read in pickit2.c has two errors:
- It drops load extended address commands unless a paged read happens at a
64k byte boundary; this is invalid when reading files with holes
- It wrongly assumed that flash memory is byte addressed
The fix is to carry out a load extended address command, if needed, at the
beginning of each paged flash read with the correct word address. Although the
pickit2_paged_load() has independent parameters page_size, addr and n_bytes,
AVRDUDE only ever calls paged read/write functions with page_size and n_bytes
both set to mem->page_size and addr aligned with a page boundary. Therefore, it
is sufficient to set the load extended address at the beginning of each page
read.
mcuee
approved these changes
Jul 11, 2022
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The paged read in pickit2.c has two errors:
64k byte boundary; this is invalid when reading files with holes
The fix is to carry out a load extended address command, if needed, at the
beginning of each paged flash read with the correct word address. Although the
pickit2_paged_load() has independent parameters page_size, addr and n_bytes,
AVRDUDE only ever calls paged read/write functions with page_size and n_bytes
both set to mem->page_size and addr aligned with a page boundary. Therefore, it
is sufficient to set the load extended address at the beginning of each page
read.