Shrapnel: Added a note about loading the compiled binaries onto the microcontroller

2011-02-28T00:20:34Z

Added a note about loading the compiled binaries onto the microcontroller

Shrapnel: Added MSP430 sample code, links, notes

2011-02-28T00:11:50Z

Added MSP430 sample code, links, notes

New page

Here are the notes from our TI MSP430 programming workshop, held 2/27/2011. Our goal was to get working build environments on our PCs and be able to program the LED on the ez430 development sticks from Texas Instruments. We succeeded!

== Code ==

Here's the blinky code we used to test the toolchain, modified from TI's blinky code to make it more readable for non-C programmers:

<code><pre><nowiki>
#include <msp430x20x3.h>

void main(void)
{
// The watchdog timer will periodically reset the chip if we haven't poked it
// Initialize the WDT (WDTPW) and turn that behavior off (WDTHOLD)
WDTCTL = WDTPW + WDTHOLD;

// Mark P1.0 as an output pin by setting P1DIR's LSB to 1
P1DIR = P1DIR | 0x01;

while (1) // Infinite loop
{
// Flip LED state
// Invert pin P1.0, port 1 bitwise XOR with 0000 0001
P1OUT = P1OUT ^ 0x01;

// Wait
i = 20000;
while ( i > 0 ) {
i--;
}
}
}
</nowiki></pre></code>

And here's some code that can make the LED pulse up and down, rather than flash on and off:

<code><pre><nowiki>
#include <msp430x20x3.h>

// Constants for pulse width increment and cycle time (sum of LED on + off time)
#define INCR 1
#define CYCLE 250

void main(void)
{
// The watchdog timer will periodically reset the chip if we haven't poked it
// Initialize the WDT (WDTPW) and turn that behavior off (WDTHOLD)
WDTCTL = WDTPW + WDTHOLD;

// Mark P1.0 as an output pin by setting P1DIR's LSB to 1
P1DIR = P1DIR | 0x01;

// Starting value for the LED pulse width
unsigned int width = 11;

// Per-cycle pulse width delta (how much longer to stay lit each cycle)
unsigned int incr = INCR;

// Loop counter
unsigned long i;

while (1) // Infinite loop
{

// == LED ON ==
// Turn on pin P1.0, port 1 bitwise OR with 0000 0001
P1OUT = P1OUT | 0x01;

// Wait
i = width;
while ( i > 0 ) {
i--;
}

// == LED OFF ==
// Turn off pin P1.0, port 1 bitwise AND with 1111 1110
P1OUT = P1OUT & 0xFE;

// Wait out the remainder of the cycle
i = CYCLE - width;
while ( i > 0 ) {
i--;
}

// == UPDATE PULSE WIDTH ==
width += incr;

// If we've hit the minimum or maximum pulse width, start moving the width
// in the other direction
if ( width >= CYCLE - 30 || width < 1) {
incr = -incr;
}

}
}
</nowiki></pre></code>

== Links ==
=== Tools ===
*[http://sourceforge.net/projects/mspgcc4/files/mspgcc4/ mspgcc4 (sourceforge.net)]
** Extract the latest tarball, run <code>./build_gcc.sh</code>
** Will download binutils, gcc, gdb, and compile them (may take a LONG time)
** Will default to installing under /opt/

*[http://mspdebug.sourceforge.net/download.html mspdebug (sourceforge.net)]
** In Ubuntu, first install dependencies: <code>apt-get install libreadline-dev libusb-dev</code>
** Put the 'mspdebug' binary in the bin/ directory established when you installed mspgcc4

=== Info ===
* [http://focus.ti.com/docs/toolsw/folders/print/ez430-f2013.html MSP430 USB Stick user's guide (ti.com)]
** Schematic of development board
** Notes on device capabilities

* [http://www.43oh.com/2010/11/a-step-by-step-guide-msp430-programming-under-linux/ Step by Step Guide To MSP430 Programming with Eclipse under Linux (43oh.com)]
** Used [http://mspdebug.sourceforge.net/download.html mspdebug] in the console to program/debug the chip
** We didn't try mspdebug + Eclipse as documented on this page, but would expect it to work well
** Couldn't get Eclipse to connect to the msp430-gdbproxy instance and debug on the device
** In the latest version of Eclipse, if using msp430-gdbproxy, use the debugger type "gdbserver Debugger" instead of "remote gdb/mi"

*[http://www.simpleavr.com/msp430-projects/ti-launchbread TI Launchbread, a practical example of wiring/coding/flashing (simpleavr.com)]

*[http://justinstech.org/2010/08/msp430-basic-codingprograming-part-1/ MSP430 basic coding & programing part 1 (justinstech.org)]

*[http://justinstech.org/2010/08/msp430-basic-codingprograming-part-2-wdt/ MSP430 basic coding & programing part 2, watchdog timer examples (justinstech.org)]

@@ Line 2: / Line 2: @@
 == Code ==
 Here's the blinky code we used to test the toolchain, modified from TI's blinky code to make it more readable for non-C programmers:
 <code><pre><nowiki>
 #include <msp430x20x3.h>
@@ Line 35: / Line 44: @@
 <code><pre><nowiki>
 #include <msp430x20x3.h>

MSP430 Workshop notes 2/27/2011 - Revision history

Shrapnel: Added a note about loading the compiled binaries onto the microcontroller

Shrapnel: Added MSP430 sample code, links, notes