As a matter of fact I was thinking about making a RAM ExtRam clone (poor man's REX ;-) and was wondering the same thing, how to avoid having to shear/grind the edges.
How'd he do that? m ----- Original Message ----- From: "Stephen Adolph" <twospru...@gmail.com> To: "Model 100 Discussion" <m100@lists.bitchin100.com> Sent: Thursday, May 26, 2016 6:43 AM Subject: Re: [M100] New option rom module > well that's very interesting; I had assumed that since my layout tool > would fail the design if I put the board edge down the middle of the > vias, that no one would build with that error. So, I hand grind REX. > > > On Thu, May 26, 2016 at 6:40 AM, Stephen Adolph <twospru...@gmail.com> wrote: >> hey, cool. didnt you get a board violation for putting the board >> perimeter in the middle of the via? >> do you need a spacer under the board when in the socket? >> >> On Thu, May 26, 2016 at 1:04 AM, Brian White <bw.al...@gmail.com> wrote: >>> Just verified a new option rom module design. >>> >>> Adapts a 28C256 SOIC to a Model 100/102/200 option rom socket. >>> >>> Allows re-programming the eeprom after the chip has been soldered to the >>> module. A pullup resistor and a jumper on-board allows enabling/disabling WE >>> on the eeprom as needed. >>> >>> There is a special programming adapter to make it convenient to re-program >>> after soldering the chip, but there's a problem with that, so at the moment >>> you can still program (re-program) using a dip28 test clip and manually >>> arranging 28 jumper wires. Not the most convenient but functional. >>> >>> This is essentially the same as "ROMBO" or "MOMBO", but now it's an open >>> source design up on oshpark and anyone can get one whenever they want. >>> >>> Home/self assembly isn't too bad. You don't need anything but the parts and >>> a plain soldering pencil and some flux and solder. The soic chip was simple >>> using the "drag technique". It's simple, just search "solder drag technique" >>> on youtube. The trick is just the extra flux pooled around for surface >>> tension. >>> >>> https://oshpark.com/shared_projects/4dLqXOs0 >>> >>> https://goo.gl/photos/Zs8ZnmDco9BwgDDBA >>> >>> -- >>> bkw
