ELEC 332

Background

Because of the limited number of pins on the MSP430F2012, we can't afford to use 8 of them to convey a byte of information to another device. Instead, we must rely on serial signaling which requires between one and four lines. There are a variety of standard protocols available, some of which are supported in hardware by the MSP430 and others which must be handled in software. This week we will look at two of these, asynchronous SIO and I²C.

This Week's Circuit

Actually, there are two new circuit modules in this week's exercise. The good news is that one of them has already been fabricated (like the connector and potentiometer modules last week). The bad news is that not only will you have to assemble the other, but you will also have to design it and lay it out.

Here's the first one, an RS232 serial interface:

(Click to enlarge) This is based on the Sipex SP3223 RS232 level converter. We will use this to provide communication between the MSP430 and programs running on the PC.

The other is an external D/A converter which we can use to overcome the deficiency in the analog output capability of our chosen branch of the MSP430 family. We'll have more to say about it later on in the program.