On 11.07.2012 10:26, Harald Welte wrote:
the core modem design is 40 x 29.8mm in size, but that of course excludes things like the sim card reader, or any other new components we may add.
So it looks like the MiniPCI Express Card on this picture http://en.wikipedia.org/wiki/File:MiniPCI_and_MiniPCI_Express_cards.jpg ?
After some first checking, that size would actually even fit nicely within the mechanical form factor of the C1xx boards, as they have at least something like 36 x 70 mm mechanical form-factor.
The question is, if you want to build a modem or re-engineer a phone for cases that:
There are some signs that the supply of Motola C1xx phones is not endless, after all.
And this include the cases as well.
Now if thre was an _easy_ way to make one circuit board that would both fit into the C1xx case _and_ also have a board edge connector for use in a back-plane, I would consider doing that.
Make it simple.
my first idea is to have a 'break away' backplane connector that one would simply break off to mount it in a phone case. But then, if it is intended to be broken (e.g. by perforating with a series of holes), the PCB might break when it is plugged into the backplane and somebody pushes it sidewise.
The 'break away' connectors came from manufacturing and they are not made to use it on "harsh" environments.
- expose JTAG
1.27mm 10 pol Pin-Header on the opposite side of the board edge connector, this make it possible to debug the board in a backplane
yes, good point. However, on that side there is likely the RF transceiver and the antenna connections :( You probably don't want the transmitter near the jtag cable...
For development that's fine i think. But this is related to the planed backplane connector.
- board-edge connector for plugging many boards into one backplane
I would suggest the ERNI SMC. There are also a cable assembly available. http://www.erni.com/fileadmin/medien/downloadcenter/smc/ERNI-SMC-e.pdf
undoubful great connectors, but I really wanted to keep it low cost, thus the proposalf of using PCIe connectors on the backplane. Needs no connector on the board itself, just a bit of board footprint.
Yes but that's only simple on one site and the board price increase because the extra milling ways but maybe for a 6 plane pcb it's not that much.
I think the initial hurdle to get it run on the table is really high with this kind of connector.
How a developer or backplane board should looks like and whats the estimated price relative to the modem price?
Regards,
Mathias