Milo, My comments are inline below.
dave ----- Original Message ----- > From: "Milo Hoffmann" <[email protected]> > To: [email protected] > Sent: Thursday, November 8, 2012 11:29:41 PM > Subject: [coreboot] BIOS Savior (RD1-PMC4/8X) unavailable? Build my own? > > Hello list, > > I might be missing something here, but I've spent all day trying to > find a vendor (anywhere) who actually carries the BIOS Savior model > I've determined I need. I did find on the ioss website that they have > stopped manufacturing (I believe that's what they were trying to say) > the models I need. [1] > I have a PLCC32 socket (holding an SST 49LF004B) and the ioss > reference page [2][3] indicates an RD1-PMC4 or RD1-8X (not 8X2). > > So... I started down the line of thought that I should be able to > build my own, or come close enough to it with a switchable solution, > for testing. > > Digging around, I found the wiki page indicating that it was possible > to build your own [4]. There was no PLCC example, so I searched a bit > more and found this [5] thread and this [6] reference. The thread > included a quick and dirty explanation of setup (provided that you > have identical chips) along with other useful hints. The reference > was less helpful unless I can get a 8Mb (1MB) flash chip that is > otherwise identical to the SST49LF004B. > > But, the thread also said I would need a "32pin PLCC-Plugin-Adapter" > for which I have found a few part numbers but no US distributor > (haven't looked international yet). > > I have the datasheet for the SST49LF004B (and two known working > chips) > but don't know the rest of the equation. > > The datasheet does not include the /CE pin from the quick and dirty > explanation. I interpret it to mean the WE# (Write Enable) pin but am > seeking confirmation from more informed folks. > > Can anyone on the list confirm I could hook up two identical > SST49LF004B, using the WE# pin, to a three wire switch and have a > functioning switchable BIOS? If you are switching between two flash devices you would want to be switching between the two CE# signals. Switching between the two WE# signals would only disable writing to one device, and reads would be sourced by both devices. You would need a separate pullup on each devices CE# signal so that when that devices CE# isn't being driven by the mother-boards CE# output that device would be disabled. The devices don't necessarily need to be the same exact device, unless there is some other constraint (e.g. size, flash support,etc). You could have a SST49LF004B in one socket and a SST49LF002 or SST49LF008 in the other socket. They wouldn't necessarily even need to be the same brand. They would both need to be FWH flash devices though. Most chipsets have a strap that determines whether the ROM R/W cycles will go out on the LPC bus as FWH or LPC-memory cycles. > Is the more elegant solution to also find a PLCC Plug (like say, > Winslow Adaptics W9302), two PLCC sockets and some board with which > to > stick them all together? > > I would really like to return the 'spare' SST49LF004B back to it's > board once I have a working coreboot firmware load. (I'm sure I'll be > asking questions about that soon too. Still trying to get a QEMU > coreboot working... hehehee...) > > Thanks for any response. > > Milo > > References: > [1] http://www.ioss.com.tw/eg/orderform0703.html > [2] > http://www.ioss.com.tw/web/English/RD1BIOSSavior/Select/RD1ModelSelectionGuide.htm > [3] > http://www.ioss.com.tw/web/English/RD1BIOSSavior/SelectionSheet.html > [4] http://www.coreboot.org/Developer_Manual/Tools/Dual_Flash > [5] > http://www.coreboot.org/pipermail/coreboot/2004-August/008798.html > [EPIA flash questions] > [6] > http://www.coreboot.org/pipermail/coreboot/2003-September/005153.html > [Homemade BIOS switch for EPIA boards (and others with 2MBit chips)] > > -- > coreboot mailing list: [email protected] > http://www.coreboot.org/mailman/listinfo/coreboot > -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
