What is difference between of msp430f6776 , msp430f67761

Hi, 

Thanks for helping me. Is there any document that I can read about this name code of msp430s ?

Hi,

you can try to refer to the MSP430 product brochure:

http://www.ti.com/lit/slab034

Usually, silicon errata are fixed with a new silicon revision. This is done in most cases, where any implemented workaround won’t break by the fix (obsolete, but still working as expected).

But in some cases, changes are not backwards compatible. In this case, an A version is released, where components and pinout are the same, but the components require some code changes (like the REF module in the 5438A, which was not there in the 5438 and required a code change to make the ADC work again, or the lower default core voltage, that requires a code action to allow >8MHz, while the 5438 did allow 18MHz from scratch)

In other cases, components are enhanced or added, while otherwise being fully backwards compatible. In this case, usually a ‘1’ version is released. In both cases, the new versions are better, but often more expensive than the original, so the original one is still sold but not recommended for new design (NRND status).