I probably missed it and can't easily find the previous discussion, but what diameter wire do you suggest? I see the hole size 0.6mm/24 mil but not the wire gauge.
Thanks! On Tue, Nov 28, 2023 at 7:56 PM Brian K. White <b.kenyo...@gmail.com> wrote: > > You have lost me. > > If you want to dump or re-write the flexrom, you can just do it it it's > programming adapter. > > I thought you wanted to dump the original rom? > > And if you want to avoid all the hardware actions while changing the > main rom, that's exactly what REX Classic allows. It's purely software > once you set that up, and even if you botch both primary and secondary > images, you only need to open the option rom compartment instead of the > whole machine to revert to the internal eeprom. > > If you have a soic-28 test clip, you *might* be able to program the > eeprom without removing from the machine. Mostly it should be ok, the > board allows the programmer to drive /WE for instance, it's definitely > ok to program the chip directly with a test clip if the board is not > installed in the machine. But but one thing I don't know is, if the > board is installed in the machine, all the pins are connected to the > bus. Mostly that should be ok but one thing I don't know is what happens > when the programmer tries to provide power on the vcc pin? Does it power > up the whole machine? Even with the memory power switch turned off, > which normally kills everything, this would be injecting power to the > rail from a point "inside the walls". > > If you're worried about the legs, and you're right that it would be a > pain to repair a loose one after the frame was cut away, I now actually > prefer gold plated plain brass wire. > https://gist.github.com/bkw777/52d85d89eeff8445cc667685d05ea94d > > The advantages are, > - just wire, no special shapes to cut off or anything, no single special > supplier > - a few feet makes hundreds of 6mm legs > - the wire is round, so there is no problem with it rotating when > loosened and resoldered > - gold plated > - repair/replacement of a broken leg is trivial > > The disadvantages are, > - each leg has to be soldered individually, no one-piece connector or > frame like with a normal pin header > - no simple supplier to point to, it's such a generic thing that there > is no part number or such, except in large quantities from bulk > suppliers. The various suppliers (for small quantities) I've found have > all been transient like Etsy or Ebay links that don't work a year later. > And it's easy to end up with gold colored aluminum wire or brass wire > that isn't gold plated (which starts tarnishing within a year), since no > one selling the stuff is writing their descriptions for electronics use. > I have also gotten wire from aliexpress that was thinner than claimed, > which ends up being too thin and weak despite you buying the correct awg > or mm number. > > But if you do get some, then you have a lifetime supply after that. > > The preloaded bom carts with the pcbs have the sil leadframes just > because it's an actual part that can be ordered normally along with > everything else, and is both a little cheaper and a little more > convenient to solder than the MillMax or Keystone micro pins which could > also be ordered as part of the bom. > > -- > bkw > > On 11/28/23 13:32, runrin wrote: > > This is a good idea, but I've already got my new EEPROM in there and > > every time I remove it and put it back in, I get worried I'll break off > > one of the legs and have to resolder it. > > > > The leadframes used to make DIP pins on Brian's FlexROM adapter board > > work well, but I really don't want to have to replace them when I > > inevitably break one off. > > > > Would you use a BASIC script to do this Mike? Just a loop to PRINT each > > byte to the COM port? > > > > On Tue, Nov 28, 2023 at 11:45:10AM -0500, Mike Stein wrote: > >> Why not just dump it out of the M100 directly? > >> > >> On Tue, Nov 28, 2023 at 9:50 AM Brian K. White <b.kenyo...@gmail.com> > >> wrote: > >>> > >>> On 11/27/23 11:48, runrin wrote: > >>>> Do you know if it's possible to dump the original ROM using the > >>>> programming adapter for the FlexROM 100? > >>> > >>> Maybe. > >>> > >>> There are two things to worry about and I'll just think out loud right > >>> here. > >>> > >>> 1 > >>> The programming adapter presents a pinout for a 28C256, not a 27C256 or > >>> mask rom. Those are only a couple wires different, but then again, since > >>> it's just for reading, and the read cycle is the same, you could just > >>> tell the programmer that it's reading a 28C256 (force it, override chip > >>> id detection), and that won't hurt the rom. > >>> > >>> 2 > >>> Pin 23. The programming adapter routes pin 27 from the programmer (/WE > >>> if a 28C256 were in the programmer) to pin 23 of the DIP socket, which > >>> is ALE on the LH535618 rom, but the flexrom board connects it to the /WE > >>> pin on the actual 28C256 on the board. > >>> > >>> I *think* what you want to do is take a DIP-28 socket and bend out pin > >>> 23, connect the bent-out pin 23 to pin 27, put the modified socket into > >>> the programming adapter and then the old rom into the modified socket. > >>> Then tell the programmer to read a 28C256 and ignore chip id. The socket > >>> is just to avoid bending the leg on the old chip. > >>> > >>> IE, feed /CE from the programmer to both /CE and ALE on the chip, and > >>> don't connect anything to /WE at the programmer. > >>> > >>> But, at that point it's almost simpler to just make the entire adapter > >>> manually with two dip sockets and wires. Especially since it's a > >>> one-off. In that case, use a 27C256 pinout and tell the programmer to > >>> read a 27C256 instead of 28C256. > >>> > >>> But if your chip has any of these part numbers, then it's already been > >>> dumped. > >>> https://bitchin100.com/wiki/index.php?title=Model_and_ROM_information > >>> > >>> -- > >>> bkw > >>> > > -- > bkw >
