Enabling 4kb sector erase and smaller erasable filesizes on winbond chips #67
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matthewcieplak
commented
Mar 14, 2020
| delayMicroseconds(1); | ||
| CSASSERT(); | ||
| if (f & FLAG_32BIT_ADDR) { | ||
| SPIPORT.transfer(0x20); |
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Here is the new special command from the winbond datasheet
matthewcieplak
changed the title
|
Not wanted: #3 |
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This feature takes advantage of winbond's 4kb sector-erase feature to enable smaller erasable filesizes.
I noticed that I couldn't save more than 16 erasable files to my winbond w25q80, and did some investigating into this library's size allocation. I discovered that it assumes all chips use 256kb erase blocks, so I added a feature detection flag for winbond chips and auto-sizing function for erasable files smaller than 256kb. (Right now this auto-size feature uses powers of two but could potentially work in 4kb blocks instead.)
This is tested in hardware on the w25q80 and seems to work fine! So far as I can tell from reading datasheets all winbond serial flash uses 4kb erase sectors, but I am not super-familiar with their product lines so would appreciate a double-check.
The erase function looks quite different but is substantially the same, and should accommodate alternate erase sector sizes if other manufacturers use them.