✧✦Catherine✦✧Feb 22

today's project for #GlasgowInterfaceExplorer: reworking the memory-25x applet

this is a very old applet, one of the first introduced. it works mostly fine, but it was designed and implemented before I really knew how to make good applet UIs, and long before I added QSPI support, so it's not using all of the available bandwidth & it requires specifying a bunch of geometry parameters by hand even when it is trivially extracted from the flash itself

I am planning to redesign the Flash command engine to support not just 1-1-1 (normal SPI) commands, but every mode including 1-1-2 and 1-1-4 (dual/quad data) and 1-2-2 and 1-4-4 (dual/quad address and data). to do this I will implement an abstraction for a (Q)SPI command set, which can then be extended and specialized by an individual flash

this will also handle devices like Winbond's and Micron's QSPI NAND devices (W25N series and MT29F series, respectively).

Show threadAndrew ZonenbergFeb 22
@whitequark what about older pre SFDP parts?
Show thread✧✦Catherine✦✧
@azonenberg you still have the option to specify it via command line
Feb 22 at 3:34pmWeb
Show thread✧✦Catherine✦✧Feb 22
@azonenberg actually a lot of "new" parts (for a pragmatic value of "new") do not have SFDP info for reasons not totally clear to me, I think some of them are just too cheap or something? some of them appear to have the SFDP memory area but it's not filled in
Show threadAndrew ZonenbergFeb 22
@whitequark huh the last non sfdp part i saw was a winbond or micron on a digilent Spartan6 devkit
Show thread✧✦Catherine✦✧Feb 22
@azonenberg how many barely-marked chinese flash memory ICs do you examine per month?
Show threadAndrew ZonenbergFeb 22
@whitequark not a lot, much of what I work with is western vendors. I've seen puya stuff but I'm pretty sure they have sfdp?
Show thread✧✦Catherine✦✧Feb 22
@azonenberg hm I'll see if I can collect some more informal statistics
Show threadAlexBFeb 24
@azonenberg @whitequark I have seen a puya with SFDP. it broke flashrom :) https://review.coreboot.org/c/flashrom/+/90131