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Need extra space for a font table!

Jake G.
Prodigy 190 points
Other Parts Discussed in Thread: MSP430F2618

Hi All,

    I recently upgraded the LCD on my project from a 128x64 (prototyping display) to a more advanced 320x240 display , which is closer to what we expect of our final product.  My issue at the moment is that we have essentially run out of memory on the MSP430f2618 for logos (large Hex array if we were to use 320x240 about 57kB) and a Bigger font table.  I was wondering if there was a way to use something like an SD card to store these tables and grab chunks of them on the fly.  Our logos only get displayed at start up to give our customer something too look at while we wait for everything to stabilize so we can take a zero measurement for our sensor, so it only needs to be loaded in a section where time is not a big constraint!  The font table might be able to be saved within the chip but the current one we have found/made is about 25kb of data so it is pushing it.

 

I am basically asking if there are any canned solutions for this problem so I am essentially not re-inventing the wheel, or if this is even possible.

 

Thanks,

Jake

  • 0
    Guru 12160 points

    Jake,

    We use SPI based NOR flash for a small data storage (4MB - 16MB).  It reads very quickly (as fast as you can run your SPI bus) and stores 4MB in small packages (5mm x 6mm) and 16MB in medium packages (6mm x 8mm).

    It's simple and can be made very low power (2uA in deep sleep mode) when not in use.  Because it's NOR flash, you don't need wear-leveling or a separate NAND controller or a file system etc.

    Jeff

  • 0
    Guru 227245 points

    There are different ways to do it. Besides getting a bigger MSP (the 5438 has 256k Flash, and the layout needs to be changed anyway to add memory or a card slot), you can add an external flash chip (there is an Atmel 64MBit = 8MB chip that can be programmed per SPI) or implement an SD card interface.

    The problem is to put the data into the flash. THis can be done by writing specialized firmware whcih contains part of the data and just programs the external memory.

    Using an SD card would allow writing it on a PC, btu then you'd have to embed a file system driver into the MSP - which eats lots of memory.

    Also, you can go and use sort of run-length-encoding on your logo. It will most likely shrink it down significally. Have a look at the PCX image standard. For a B/W image, <50% are typical. And it takes almost no time or memory to decode. Same for the font table, if you only need to store it for upload to the display. You cna store it ompressed and decompress it while sending it to the display.

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