Nokia LCD, nunchuck, and MSP430 join forces

[JB's] driving a Nokia 6100 LCD using an MSP430 with input from a Wii Nunchuck. He’s using the G2211 microprocessor that came with the Launchpad, and developing his code with MSP-GCC. As you can see in the video after the break, this works but there’s some room for improvement. That’s being said, he is bumping up against the code memory limit, with just around 500 bytes left to work with. The LCD screen is SPI and currently it’s hogging the pins that are used for the hardware i2c. Since he needs an i2c bus to talk to the nunchuck he had to go with software i2c which explains part of his program memory troubles.

We’re in no way experts on this, but it seems like he could save space (and improve the input responsiveness) by rewriting his LCD drivers in order to remap the pins. Then again, it might just be better to move up to a larger MSP430. If you’ve got some advice, make sure to share it by leaving a comment.

Comments

  1. MigSantiago says:

    Nice project!

    Yeah, the Nokia 6100 SPI pulses can actually be generated using bit bang and the output pins don’t need to be hardware controlled. SPI via software is easy.

    BTW, I re-wrote a Nokia 6100 library from an AVR to a PIC32. The code can be migrated to any other uC out there:

    http://goo.gl/2O33S

  2. uC says:

    It should be possible to drive multiple i2c devices with one micro. i2c is a master slave setup.

    I peeked at the code and I think there should be plenty of speed left.

    Looking forward to seeing more of this.

  3. GCL says:

    @uC
    Correct. That was its intended purpose. TI sells a second source of a Phillips/NXP device that breaks out the I2C output into an eight bit I/O point.

    I looked at the guy’s pages and it seems he’s got an idea there but I wonder….

    Now how can we drive just the Nokia screen? I have a screen here, but have had no luck with it at all.

  4. Dekar says:

    I don’t see why you’d use a weak µC. I started with microcontrollers earlier last year and my first one was a stm32 with 72mhz, 64kb ram and 512kb flash. They’re just a few bucks and they have enough power for about anything :) (And pins ofc!)

  5. Roberto says:

    How fast can this LCD flash dark to clear to dark? Would it be possible to make open hardware active shutter glasses for the price of parts ($24) rather than what nVidia wants for a pair? ($170)

  6. vtl says:

    The biggest issue with the Launchpad chips is the lack of memory. If you are comfortable with soldering TSSOP or QFP chips (its not as difficult as you might think) then get yourself some better MSP chips. Texas offers free samples for most of their gear. Just make sure you get chips with spy-bi-wire, msp430f5xxx are pretty beefy and would be a nice chip to start with.

    You can buy QFP breakout boards from ebay for a few dollars.

  7. Bart B says:

    I recently got an email from TI announcing new microcontrollers in the low cost series with 8K’s of flash and 20 pins.

    Check out the following part numbers: MSP430G2402, MSP430G2432, MSP430G2452

  8. daniel says:

    yeah amazing I gonna try this out!! hope I get it work!!

  9. cde says:

    The new Valueline Chips with 20pins and more memory are already out.

    And he could pull dual purpose on the USI, since spi uses a Chip Enable to make it active, and i2c uses a start/stop sequence and addressing.

  10. GCL says:

    @Bart B
    When did you get this e-mail? Was it delivered on a Sunday as part of its regular weekly briefing? TI does send them out.

  11. NatureTM says:

    @Dekar

    I feel like using a weak uC is part of the fun and definitely more impressive. Personally, I get a lot of satisfaction out of squeezing every last drop of performance out of a chip. It’s nice to be able to surprise yourself. Also, employers will be happy if you can trim a few cents off the BOM by coding efficiently.

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