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LaunchPad Experimenter's Board

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I am thinking of making an experimenter's board that could be used with LaunchPad.

It would be a 4" x 4" board with ~1" standoffs on each corner. LaunchPad would be attached from the bottom. Stacking headers would allow Booster Packs to be attached on the top. LaunchPad headers would be either in the center or top center (this would make LP stick out a little bit, but would make easier access to USB connector and some jumpers.)

What would be on the board? Your basic stuff, LEDs, power supply, some switches (one joystick type switch,) memory, shift registers, maybe LCD or at least a header for it, configuration jumpers, maybe power transistors, etc.

Any ideas what else would be useful?

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That is excellent, exactly what I had in mind.

I see you are using 14 pins only, is that because it was created in the pre 2553 era?


Things I missed: RS323, RTC (SPI,) potentiometers.

Oh, an external xtal oscillator driver, demultiplexer and multiplexers to simplify configuration jumpers.


Other: LDR, IR detector/transmitter, speaker/piezo (thanks rcouto.)


Some more thoughts.

Instead of stacking headers, regular headers but with port pins connected through config switches/demux. This would allow some ports on Booster Packs to be re-mapped.


Another thing, standardization of ports. Right now, every Booster Pack uses random ports for things like CS. It would be nice to have some sort of standard, like P2.0 will be used to select display, P2.1 to select memory, etc.


Also, ports P2.0 to P2.2 could be used with demultiplexer (138) for addressing attached devices. 000 would be no devices selected, 001 display, 010 memory, 011, something else, 111 global reset, etc.

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Hmmm..fatihinanc, you never told us about this one. Do you have a writeup on this so I can link it through the Blog?


Might I suggest a FTDI instead of RS232? Most of the time one would have to use a serial-usb converter anyway... and of course, a prototyping area can never hurt!

I'd prefer a USB/RS232 port too. D-Sub 9s take too much space.


Here is what I am currently using on the side

http://www.embeddedmarket.com/products/ ... ose-Board/

Some of it could be used as inspiration

Nice find.

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Awesome idea!


Might I suggest a FTDI instead of RS232? Most of the time one would have to use a serial-usb converter anyway... and of course, a prototyping area can never hurt!





If the LP already has USB->Uart, is an extra one needed? Not sure if you're looking for a higher speed than the 9600 the LP supports.

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If the LP already has USB->Uart, is an extra one needed?

The TIUSB is sort of a hit-and-miss (and mostly miss at that). An Argentinian butterfly flaps its wings in Buenos Aires and Norway's TIUSBs stop working. FTDIs just work.


Please, TI, please, with cherry on top, you can do it properly!

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I was thinking in my spare time about this board today, and here's what I came up with so far.


1. What's included

LCD - HD44780 with serial input, 5110 could be an option





digital pot (SPI)

595 (possibly two, one with high current driver)

input expander (didn't decide on that one yet, but it could include an analog switch)


FTDI (which one?)

4 RGB LEDs (I am thinking that there is no need for a single color LEDs)

IR detector (38kHz)

IR diode

2 opto-triacs and/or opto-darlingtons

16MHz crystal oscillator connected to XIN

4 power transistors BJTs or MOSFETs (both polarities?)

4-direction switch

4 push buttons

2 potentiometers

PS style joystick (if there's any room left)

audio amp and speaker or piezo

LDR (hmmm)

3.6V & 5V power supply or regulator


2. Header for Booster Packs?

I am thinking no. Remapping ports would be a big hassle, but then again, might be worth including.


3. Mapping analog ports

The easiest way would be to use double row female header and use 5cm M-M jumpers. For most common tasks, M-M headers with soldered wires or a little board could be used allowing quick "re-programming"


4. Selecting SPI devices (does anyone want I2C?)

Below image illustrates what I have in mind for selecting SPI devices and their special functions. All SPI devices will be controlled by P2.0-P2.5. Extra gate is for SRAM hold. Inverting buffers might be needed for some things since 259 is active high. Small functions will be necessary to select/deselect devices, however, it will be easy to port the software by simply replacing the function with port bit manipulation instruction.


5. Serial comm

Unless I come up with a nice digital switch, a 4x2 header will be used to connect serial gizmos to the MCU. Possible connections: RS232 <-> MCU, FTDI <-> MCU, MCU <-> SPI1 bus (I am assuming there might be a need to use both SPI modules,) RS232 loopback, FTDI <-> RS232. Some can be used at the same time.



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It kinda reminds me of those 1001 Electronic Kits you could get at Radio Shack in the 70's.

I used to have one :)


There is a lot of copper on a 4" x 4" board, it would be a shame to waste it. I think there should be as many things as possible on that board, but it doesn't mean you have to have them all installed.


Re: 4

Which approach is better for CS, using demux's or simple headers?

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For the low-speed peripherals (RTC, poti, possibly EEPROM) I would prefer I2C. The addresses make it easier to use them all at the same time and still have a lot of GPIOs available. Is there a specific reason (besides speed) that you prefer SPI?


Oh, and just to make sure: by 4" x 4" you mean 10cm x 10cm, right?





Edit: The standard FT232R from FTDI should be enough for a simple usb-uart connection. The 4 GPIOs could be routed to headers for easy access.

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6. Decided that IR will not be on the board. Instead, 3 pin male headers will be available: VCC-DATA-GND. IR detector or a 1-wire device can be soldered to a female header and plugged in.


7. No audio amp, but how about op-amp/comparator?



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