Stellaris Cortex M4F Launchpad

Some time ago I ordered from TI a couple of Stellaris launchpads, but unfortunately I did not have much time to play with this new toy, lately I dug it out and gave it a go...

First of all, the Stellaris launchpad is powered by a Cortex M4F 120H5QR MCU, which is quite "a beast", running @ 80MHz, floating point capabilities and internal 256KB Flash Memory.

It is packed with plenty of peripherals, ranging from 8 UARTS, 4SPI, 4 I2C, CAN, ADC12 (1MSPS!!), a flexible clocking system, timers, DMA (32Ch!) etc.

There is quite a lot to explore, as you can see.

The launchpad comes in the usual format (and fancy red color) and also has the typical headers, both male and females on the opposite side of the pcb.

Other connections are two MICRO USB (yup, they went for the micro option with these ones, just to make you mess around with cables I guess :) ), one of which you will use to access the board via the FTDI / JTAG interface.

I am using Code Composer Studio and the free software library (containing some examples) StellarisWare, from TI.

Loading a project and debugging it is as easy as it can get, just remember to switch the power select towards the micro usb connector, that will power the board from it, connect the usb to your pc and fire up CCS.
TI Resource Explores shows StellarisWare installed (did not work on my previous installation, had issues with CCSV5.2, 5.4 seems to do its job neatly), browse to find the blinky example (I always like to blink leds as the first project) and... it works.

Apparently the on board multi color LED is connected to the GPIO port F, normally these leds use 3 colors, so it is easy to guess that on that port there will be 3 bits controlling the 3 color components.
Instead of checking the manual I decided to experiment with the bits until I found the color components.

But , let's see the example code (from TI) :

int
main(void)
{
    volatile unsigned long ulLoop;
    // Enable the GPIO port that is used for the on-board LED.
    SYSCTL_RCGC2_R = SYSCTL_RCGC2_GPIOF;
    // Do a dummy read to insert a few cycles after enabling the peripheral.
    ulLoop = SYSCTL_RCGC2_R;
    unsigned int color = 0x08; // 2 is red, 4 blue, 8 green 
        
    // Enable the GPIO pin for the LED (PF3).  Set the direction as output, and
    // enable the GPIO pin for digital function.
    GPIO_PORTF_DIR_R = color;
    GPIO_PORTF_DEN_R = color;
    while(1)
    {
        // Turn on the LED.
        GPIO_PORTF_DATA_R |= color;

        // Delay for a bit.
        for(ulLoop = 0; ulLoop < 200000; ulLoop++)
        {
        }
        // Turn off the LED.
        GPIO_PORTF_DATA_R &= ~(color);
// Delay for a bit.
        for(ulLoop = 0; ulLoop < 200000; ulLoop++)
        {
        }
    }
}

The original program had a constant 0x08 instead of the variable color, but I thought this way it was a bit easier to experiment with the colors.
Turns out that the bit 1 (2^1) corresponds to the red component, bit 2 (2^2) to the blue and 2^3 to the green one.
You can combine them i.e. using 0x0E (2+4+8) to get a white(ish) color.

Besides that it appears a typical gpio management :
   SYSCTL_RCGC2_R = SYSCTL_RCGC2_GPIOF; 
This enables the GPIO port F
    GPIO_PORTF_DIR_R = color;
    GPIO_PORTF_DEN_R = color;
Direction of bits on port F is set to output for the bit that correspond to the desired color

    GPIO_PORTF_DATA_R |= color;

    GPIO_PORTF_DATA_R &= ~(color);

Or turns the bits on and AND+NOT turns them off, as usual.

Ok, I know, not much, right?

Still, it's a fancy colored led blinking and most of all you can use it to check your environment is properly set up, it worked for me :)

Promise I will find some more interesting experiments soon.