Just posted this over at Sparkfun… thought I’d post it here as well, as I think GHI ought to get in on this at the ground level ;D
[quote]One of the great advantages of using an Arduino as a hobbyist is that it’s often possible to pull the programmed MCU from the Arduino board and drop it into a custom-made (or protoboard-constructed) permanent home. This is cheap and easy.
For those who prefer the NETMF solutions such as the Netduino or FEZ line of products, things aren’t so easy. These MCUs come in LQFP packages which, even if one had the skills and equipment to solder, would require a custom board to be designed and produced.
I propose a breakout board for the USBizi100 and/or USBizi144 chipsets (based on the LPC2387/LPC2388), available from GHI Electronics here. The chipset itself isn’t extremely expensive at $13.18 in quantities of 100. A simple board containing only the bare-minimum required components (which, I believe, consists of simply a crystal and a couple of caps) could be manufactured easily and cheaply, and could provide the same type of modularity to those of us that love the power and flexibility of the NETMF platform.
The FEZ Mini is nearly such a board, but it still has a voltage regulator, LDR button, LED, and USB interface on-board. It’s also the same price as a Panda II ($40), so it’s not useful as a cheap permanent replacement for my Panda II.
@ godefroi - the eagle files are open source, so why not design what you want and have a pcb fab house make a few? I’m sure you could find some interest here (myself included). You might even be able to find a fellow forum member to do the design if it’s not in your skill set. I’ve pondered the same idea for an LED project I’ve prototyped, but have no exp. doing surface mount hardware.
I could probably work up a design in Eagle, and I could even have the PCB fabbed, but doing the SMD soldering to put the thing together is beyond my skills.
So basically a SMD chip on a PCB with pins to stick onto a other PCB?
Sounds reasonable and easy. You would need to make sure that the PCB you are sticking it on hasthe necessary voltage regulations and such.
If you really think that there is a resonable demand for something like this. I.E. its important enough for you and / or you will get your money back for PCB fab and parts population i could easily make this board for you.
I would like to see this as well. As a matter of fact, I was thinking about this this morning, but didn’t had the time to post. For a hobbyist the package of the USBizi is nearly impossible to solder, so a breakout board would come in handy for those more permanent installments.
It should only consist of the crystal with caps and the crystal with caps for the RTC (as I read on most datasheets they should be as close as possible to the chip).
Even better would be if the USBizi were mounted in the dev board using a socket (i.e. LGA 1155 CPU type) then it might be possible for the hobbyist to solder a matching socket on the permanent PCB and just pop the chip out of the dev and into production. Maybe there’s a gap here that Schmartboard (http://schmartboard.com/) could help fill also. I haven’t tried one of their boards but it’s a neat idea.
I didn’t mean an LGA 1155 literally… I meant the same type of lift-out socket design. [Insert the correct socket # here if one exists that fits the USBizi]
Interestingly enough, there does seem to be some LQFP sockets… I didn’t look long enough to see if there are 14x14mm LQFP100 package sockets, but I imagine there are. They’re usually known as “programming sockets” and are used for programming/testing. Unfortuantely, the footprint of the socket doesn’t generally seem to be much more solder-friendly than the LQFP100…
An Eagle novice am I, but I think I’d like to help out here.
Lets talk requirements.
Personally, I think if we’re going to have something like this we probably want it on .1" headers (like the Mini is) so that the header doesn’t become the “next hard thing” for someone who wants to prototype with this.
You could even make it breadboard friendly. Two long rows of pins. Depending on the pins you want, that could be a very long board though
I reckon if Gus can solder on USBizi, so can anyone else (ok so I am joking, but I am not freaked out as much as I was previously!). As long as you get good quality PCBs made you have a great chance of doing that successfully, I think.
What other thoughts are there? What should we put on and what should we not ?
QFP & LQFP is not hard to solder at all. The magic is mainly in the paste that you use.
You just need to get your technique down. Actually i prefer to solder a QFN than any other package. Sounds nuts to most but i can solder a QFN faster than the other package types. Except BGA
I would not bring every pin out, pick the most common / needed pins and bring them out to .1" headers.
as for the rest i would just put DIL pins for the user is they wish to gain access to the others that are not so common. this way you can keep the board small.
