Question

I need a different way to have global access to 160*160 bits of data, that wont cause me to run out of ram. I am trying to create a back buffer for a 160*160 LCD black and white screen. so 160*10 ints gives me 160*160 bits because a int is 16bits. However I am running out of RAM on the board. Does anyone have a way to this where I wont use the ram? maybe allocating in someway? but I cant seem to get a proper way to allocate a 2d array. Is there any other way of doing this?

edit:
it is a msp430 rbx430 board,(here is a link to a picture of it http://i.ytimg.com/vi/rr18why8wzY/0.jpg ) and yes int’s are 16bits on this device. longs and doubles are 32bits. the device has 64k memory, and I am running it at 16mhz. I am asking for 3,200 bytes

as for it making sense, how does it not? I have a 64k device, where int’s are 16bits. I am creating a map for the 160*160 lcd screen by using the 1’s and 0’s to keep track of when a pixel is on or off. after i turn on all the pixels i want, i then take my map and apply it to the lcd. This way I do not have to draw to the lcd then erase the lcd then draw again. I can simply draw, and then draw over it. this will make it so it will not flicker.

effectively creating a back buffer to draw to the lcd.

static int lcdPixels[160][10];

    /*Must call this before using RBX430_graphics*/
    void initGraphics(void)
    {

        int h = 0;
        int w = 0;

        for(h=0; h < ROW_SIZE; h++)
        {
            for(w=0; w < COLUMN_SIZE; w++)
            {
                lcdPixels[h][w] = 0;
            }
        }
    }

———————————here is the rest———————–

void pixelOn(int posX, int posY)
{
    // first grab the right column
    int column = ( ((float)posX/16.0f) + 0.9f);
    // next grab the right bit
    int bit = posX;
    while(bit > 16)
    {
        bit = bit - 16;
    }

    //turn on the bit/pixel
    lcdPixels[posY][column] |= (1 << bit);
}

void pixelOFF(int posX, int posY)
{
    // first grab the right column
    int column = ( ((float)posX/16.0f) + 0.9f);
    // next grab the right bit
    int bit = posX;
    while(bit > 16)
    {
        bit = bit - 16;
    }

    //turn off the bit/pixel
    lcdPixels[posY][column] &= ~(1 << bit);
}

/* Call this to commit the current backBuffer to the LCD display*/
void commitBuffer(void)
{
    int h = 0;
    int w = 0;
    int k = 0;

    for(h=0; h < ROW_SIZE; h++)
    {
        for(w=0; w < COLUMN_SIZE; w++)
        {
            for(k=0; k < INT_SIZE; k++)
            {
                if((lcdPixels[h][w] & (1 << k)) >> k)
                {
                    lcd_point(((w * 16) + k), h, ON);
                }
                else
                {
                    lcd_point(((w * 16) + k), h, OFF);
                }
            }
        }
    }
}

So i now tried to allocate the array using malloc, and that is a no go as well. I guess I just can not do this, 160*160 bits is just to much data….

Answer 1

Do you have 64K of RAM or 64K of Flash memory? I think the RBX430 has a msp430f2274 on it (http://www.ti.com/product/msp430f2274) which only has 1K of RAM.