Charles Steinkuehler wrote: > > Mike Noyes got the sst guys to send a schematic and some details about their > ATA-Disk module (ADM) and it's write-protect features: >
> > >Here is the 40pin 5V ADM schematic. This is using the LD017 > > >controller. In the schematic R8 is used as an option for WP. I think this is the crux. It's being used. It's being tied to ground by the presense of ground on IDE cable pin 30, and the existence of a zero-ohm resistor, ie. a short to gnd. > > >The ADM using the LD016 was never released to production. It was build > > >for customer evaluation purpuses, only, and it does not support the WP > feature. > > > > > ><<LD017 SADM.doc>> > > Looking at the schematic, taking into account the information above, it > looks like the ADM *DOES* support a write-protect function, but it's not in > the form of an easily accessible jumper. What I have determined: > > * If you have an ADM module using the LD017 controller chip, you can enable > a write-protect function (per above comments). Note that the write-protect > feature is particular to THIS SPECIFIC DEVICE, and is not a general feature > of IDE devices. Not a general feature if IDE I would agree. For a regular IDE drive, disconnecting or strapping an IDE pin low or high, such as DIOW or DIOR (23 or 25 I think) would interrupt the writing of command signals to the drive's onboard controller. At least that's how I understand it so far. > * There is a zero-ohm resistor (used as a build-time configuration option) > to connect the write protect line of the controller IC to pin 30 of the IDE > interface (from the above comments, and the schematic). > - If R8 is populated, pin 30 controls the write-protect Isn't pin30 gnd on all mainboards? If so, then the R8 being populated means this gnd is present on the DOM controller and the fact that it's write capable infers that gnd=write. > - If R8 is vacent, the device behaves normally (ie no write-protect) I see the exact opposite. It's gnd now according to the docs with R8 present and it's write enabled. If you remove R8, then you are trying to do the opposite, ie protect it. But is floating it correct? > Interpolating a bit, since I don't have a unit to test, and the PDF doc > indicates a WP# jumper that doesn't exist: > > The device should be write-protected if you tie the write-protect line from > the controller chip to ground. Since R8 is between the controller's > write-protect signal and IDE pin 30 (which should be ground on a standard > IDE cable), it should be possible to place a switch across the pads of the > (presumably missing) resistor R8. If the switch is "on", or shorted, the > device should be write-protected. If the switch is "off", or open, writes > should be possible. > > Can someone with one of these units physically look to see if there is a > missing resistor "R8" anywhere on the board? One end should go to pin 30 on > the IDE connector, while the other end goes to pin 62 of the controller > chip, according to the schematic I recieved. > > Charles Steinkuehler > http://lrp.steinkuehler.net > http://c0wz.steinkuehler.net (lrp.c0wz.com mirror) > > _______________________________________________ > Leaf-devel mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/leaf-devel _______________________________________________ Leaf-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/leaf-devel
