I love the Freedom boards, like the most recent FRDM-KL46Z for about US$15. But if I think that the ‘Freedom’ board is to big, cost too much and has too much on it, then here is one which is built for only US$5 :-): The MC HCK (pronounced “McHack”):
Basically it is a PCB board which I can build and assemble myself with SMD components (some soldering skills required). It plugs directly into a USB port, but can be powered from batteries too.
💡 With the USB connector, the board can run a bootloader or a DFU updater. I’m only wondering how they managed to get USB without the usual needed external crystal for Freescale USB microcontrollers? According to a comment on Hack-a-Day “it works”, but not sure how reliable’?
It is very versatile, and you can populate it with your own parts as desired: SPI or I2C external memory, LiPo charger, regulators, or even the nRF24L01 I used here.
A Freescale Kinetis K20 (ARM-Cortex M4) in QFP48 package can be put on the board. There is no SWD/JTAG header on the board, so you need to pre-program the microprocessor or use an adapter to the SWD pins. The Bus Master or Bus Pirate can be used for this (see this Wiki).
In summary: this is really an interesting low-cost project. With the low-cost, the versatility and the simplicity of this board I can imagine that it will be used for many projects.
Happy HCKing 🙂