Tuesday, July 9, 2013

Miniature MSP430 Programming Connector

The MSP430 is perfect for low-power and super miniature projects. Not only are smaller circuit boards cheaper to make, but they are desirable in many applications; such as in wireless sensor nodes, wearable electronics, and others. Standard 0.1" headers are simply too big for very small boards. To reduce the size requirement for the programming header, I have started using 0.05" headers. With this post, I would like to share how I use smaller headers to easily make my projects smaller and more cost efficient.



Due to how cheap the MSP430 LaunchPad is, it is often the best way to program your custom MSP430 boards. One of my earlier posts details how I use the LaunchPad to easily program custom boards using a 6 pin 0.1" header. It is important to me that I include both the UART RXD and TXD pins in the programming header for debugging purposes.


The simple schematic is shown above. Using a 3x2 pin 0.05" header on the target board, I created a "converter" board which connects to the LaunchPad using a 6 pin 0.1" header. Additionally, if I want to reduce the footprint further, I can use only a single 3x1 pin 0.05" header, ignoring the VCC, RXD, and TXD pins (as long as the target device is self powered).


The circuit board is shown above. It is very simple, yet very effective. The overall footprint of the programming header has been reduced significantly. Some possible improvements include the addition of a switch to allow you to choose if the device will be powered by the programmer or not, a protection diode for VCC, and a reset push button for those devices which are too small to have one. If you use the Eagle file provided below to make your own, please keep the URL to my blogs on the silkscreen.

Parts:

For almost no cost at all, you now have a miniature MSP430 programming header that you can use on all of your future projects. This concludes my small but useful post.

6 comments:

  1. Nice post NJC. Can you please include the part numbers/links for the grey programming wire and female header. I was also wondering if there exists an orientation-safe header (those with little notches)

    ReplyDelete
    Replies
    1. I am actually using a 2x5 connector which comes with the CC Debugger kit from TI. I'm sure that an orientation-safe header in that size exists, but I have not done an in depth search for one. These ribbon cables are quite difficult to find. Sorry that I cannot provide a part number. If you happen to find one, I would greatly appreciate it if you could post your results. In the meantime, I will keep searching.

      Delete
  2. Hi NJC, I also can't find Receptacles (female header) at mouser. Only 855-M50-3200345, but that's not vertical.

    I think, I'll use 2mm pitch connectors.

    ReplyDelete
  3. If you were to swap GND and TXD then the pinout would be exactly the same as the standard 6 pin AVR programming port (other than the size). This could be handy when people use the same pinout in .1 spacing they could utilize the same common usbtiny programmer for both AVR and msp430 with some modifications to the programmer firmware.

    Also, I hate that the eZ430 SIL pinout has Vcc and GND symmetric, accidentally plug it in backwards and fry your board. gah. the 3x2 layout fixes this at least...

    ReplyDelete
    Replies
    1. Very good point. I especially agree with the fact the VCC and GND can easily be reversed. It would have been nice to have the staggered in some way.

      Delete