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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/tasks.html | 37 |
1 files changed, 36 insertions, 1 deletions
diff --git a/docs/tasks.html b/docs/tasks.html index f379f222..e8224a1b 100644 --- a/docs/tasks.html +++ b/docs/tasks.html @@ -364,9 +364,44 @@ </ul> </li> <li> - Apparently, leaving HOLD# and WP# pins floating (unconnected) isn't a good idea. + Apparently, leaving HOLD and WP pins floating (unconnected) isn't a good idea. Information online says that this needs to be connected along with 3.3V - look into this. (it is specific to each flash chip, so read the datasheets). + <ul> + <li> + eg http://flashrom.org/FT2232SPI_Programmer - + " The WP# and HOLD# pins should be tied to VCC! If you leave them unconnected you'll likely experience strange issues." + </li> + <li> + <pehjota> stefanct: We've never had any "strange issues" with leaving WP# and HOLD# + unconnected on the Macronix and Atmel SOIC-8 and SOIC-16 flash chips on the X200. + IIRC, the datasheets don't say how those pins are wired internally or whether they can + be left unconnected. But I tested their voltages while flashing, and they float high + on their own, so they seem to support it fine. + </li> + <li> + <pehjota> fchmmr: You would connect the WP# and HOLD# pins to 3.3 V (on an ATX PSU you'd + hook up more cables to the other orange pins, with your PSU I guess you'd wrap more wires + around the 3.3-V screw), just like you do VCC. But as I said above, it doesn't seem to + be necessary (WP# and HOLD# seem to be held high already).<br/> + <pehjota> I got a solid ~3.3 V (i.e. pulled high, not floating between high and low) + from WP# and HOLD# with just VCC, GND, MOSI, MISO, CS#, and SCLK connected. Plus, we haven't + had any write protection issues as I'd expect from floating WP# and HOLD#, AFAIK.<br/> + <pehjota> fchmmr: These pins do nothing if they're held high. The "#" (not) means they cause different behavior when held low. + </li> + <li> + <stefanct> fchmmr: pehjota: it may not be a problem if the chip is soldered to the x200, but it surely is when it isnt. + </li> + <li> + <stefanct> yes... + <stefanct> a small note noting that would be appreciated because there are enough people out there already that ignore those pins and get stuck + >pehjota> stefanct: You mean a note in the libreboot documentation explaining why we don't have to connect HOLD# and WP# to anything and how they would have to be tied to VCC on a chip not soldered to a board? + <Kamilion> How about a more useful note that explains the whole discussion you two had succinctly? + <Kamilion> Not everyone is going to be an EE to know about the # indicating the pin should be pulled low to be active. + <Kamilion> reminds me, I need to pull out my pomona and try to fix some intel NIC roms + <stefanct> pehjota: yes + </li> + </ul> </li> <li> Adapt the notes at <a href="install/bbb_setup.html#stability">install/bbb_setup.html#stability</a> |