i just tried the ...usi08.c under avrgcc and it works.
[EDIT] example code should be msp430x20x3_usi_07.c (master example)
i don't have a slave and hooked it up instead to a pcf8563 rtc chip and changed the slave address (0xa2)
it may be confusing as the time delay is 5000 counts between transmissions and it's like 200Hz, u may think that the led is constant on. i changed the time delay count to 50000 and it clearly shows on-off-on.
USICTL1 |= USIIFG; // Set flag and start communication
LPM0; // CPU off, await USI interrupt
_NOP(); // Used for IAR
for (i = 0; i < 50000; i++); // Dummy delay between communication cycles, change to 50000 for better visual
i also verify by changing the slave address to something else and got constant led on. this verifies the master code works.
can u try to change your delay count to eliminate the led flicking confusion?
if that still doesn't work, may be it's a slave side problem.
personally i won't use this code unless i am doing i2c all the time, software i2c is a lot more flexible and does not take up much space. and u can do it w/ any pins.