The Freescale Freedom development boards come in several different flavors and at several different price points. It is pretty clear that Freescale counts up pennies to hit their desired target price. For example, the costlier boards with bigger processors (like the K64F which costs about $35) has sockets to fit an Arduino shield or other external connections. Many of the cheaper boards (like the KL25Z for $13) just has PCB holes. If you want to add sockets, that’s on you.
The $30 K22F board has the sockets, but it also omits a few components that are on the PCB. [Erich Styger] noted that there was a micro SD card socket footprint on the board and wondered if he could add an SD card to the board by just soldering on the socket. The answer: yes!
Other boards use a similar socket and [Erich] identified it as an SD-105027-001 (PDF) from Molex–a dollar part. Soldering the socket on the board wasn’t too hard since the pads have some solder on them already. [Erich] used some additional solder paste and notes that the corner ground pads under the socket are the hardest to get to. You’ll need a thin iron tip.
The board wouldn’t be a bad platform to build the signal generator project we covered earlier that used the K64F). The K22F has 128K of RAM, 512K of flash, and can run at 120MHz. It even has a floating point unit on board. Not bad for $30.
We’ve covered how to get started with mbed on a KL25Z (see the video below, also) and using this board would be almost exactly the same. You just need to select K22F as the target and account for any I/O pin differences. In addition to that tutorial and the signal generator, we’ve also looked at using a similar board as a mouse (coincidentally, another project from [Erich]).
How impressive.
Its mbed not mBed… Just for sure.
It makes me wonder how many budget motherboards would do that, if one just soldered on the right connectors to the empty spots that look like they would take one? Do people do that? Is that a thing?
They do that on some PC motherboard – basically the variants uses different BOM of the same PCB. You’ll need to reflow in the chips too, so you are better off buying the deluxe version of that.
I’ve really only seen that with different IC’s in the same place. You would have to remove one to get the other…
I have seen ones that have Firewire, RAID (or SCSI for really old junk) variants of the same motherboard. They just leave out the entire block.
I have done my share of reverse engineering to add extra USB or serial port to simple stuff like DSL modem, router that are not documented elsewhere on the net or have a schematic available in public.
I’ll bet that the schematic of the K22 board even documented the connector with a NC or DEPOP etc.
Yep, iirc, it the datasheet even gives you a steer on the correct part to order (same for the unpopulated Bluetooth).
Yes.
For example….
Early Nintendo Wii’s have the Gamecube sockets for the memory cards and controllers. A later revision removed that hardware but it was discovered the solder pads were still there so the hardware could be added. Support is/was still in the firmware IIRC. Later revisions excluded those pads entirely.
A version of the Atari 2600 Flashback also has pads to add the cartridge port, though you do have to cannabilize an existing 2600 to get the parts so I’m mystified as to why anyone would want to do this.
As for actual PC motherboards, I can’t really recall too many missing hardware. Not any worth noting. I believe some very early boards would have space for extra RAM banks in the days before RAM was added as cards.
I have ASRock H81M-GL LGA 1150 micro ATX board with 4 SATA sockets and two additional SATA socket footprints (plus few passives missing)
B85M-GL uses very same PCB, but has all 6 SATA ports + additional USB 3.0 socket populated
H81 chipset exposes 4 sata ports, B85 is most likely same silicon with different set of restrictions (6 sata etc). Typical market segmentation by Intel.
One example was even featured on Hackaday: http://hackaday.com/2012/05/24/grab-your-iron-and-add-gamecube-back-to-the-wii/
You can also use old 5.25″ floppy cables or a piece of an ISA slot for the edge connector. The only particularly special parts are the pins that expose the PCB, and a couple skinny bolts can do that job.
I’m growing worry of seeing the mbed online IDE on HaD, It is the worst IDE ever, broken And laggy.
Looking at the project, the author appears to be using the Kinetis full IDE, running FreeRTOS on the board. With a FAT filesystem! And a shell! That is pretty flooring.