Using the Free Flash on the B2


I’m thinking of utilising the free SPI flash on the B2, so just a few questions before I start. The B2 notes say that the top half is free, so I should be safe to use locations 0x20000 up to 0x3FFFF? It looks like the bootloader Verilog code is in bootloader/verilog/usb_spi_bridge_ep.v, so I should be able to look at this code and borrow some of it? Finally, it would be useful for the B2 programmer to be able to program the top half of the SPI flash; do you think the modification would be hard to do (I don’t know Python :slight_smile: )?

Thanks, Warren


I recommend using 0x50000 through 0x7FFFF. That will give you about 1.5 megabits to work with. There is another smaller free area from 0x20000 to 0x2FFFF that is about 0.5 megabits.

The memory is split up in this way because the absolute maximum configuration size is a few hundred bytes larger than 1 megabit and the multi-boot capability only seems to allow boot configuration selection down to the 0.5 megabit.