DIY Spi Bi Wire interface/programmer.

I do not want to buy a EZ430 board or anything coz it relies on me having to buy off the internet. With that fact in mind (pls dont tell me other ways, just want to know how to build the programmer). Is there a way i can interface my MSP4302013 that uses a SPI BI WIRE interface to my computer. Is there a way i could just connect the two wires into pins in the serial port and let some software do the rest?

Otherwise is there a circuit with relatively easily attainable parts to build. Preferably something i can breadboard and without another IC if possible??

The unit is so cheap that there isn’t any point in building your own. You could order one of the Olimex MSP-JTAG-TINY units by post.

Leon

Is there a way i could just connect the two wires into pins in the serial port and let some software do the rest?

In principle, yes. One wire is output from PC. The other wire is bi-directional. Do you know how to write the "some software"?

Preferably something i can breadboard and without another IC if possible?

In principle, yes. How about 10000 transistors?

This cracks me up. Yes, you probably could build an interface and reverse engineer the spibiwire protocol. But then you could probably walk to Texas faster and pick one up.

No ICs, chuckle…

Since you specifically asked to not hear alternate ways, I won’t tell you.

I made a parallel port programmer for the MSP430, but it was JTAG, not spy by wire.

When i say “no other ways” i mean dont just tell me to buy it because it’s easier or whatever. Then their would be no reason for me posting this question right. If an IC is needed then what would it be and the circuit of the programmer.

Even if an IC is needed to create the Spi Bi Wire protocol and then output it through the two SBW pins then there must be some sort of software to emulate this. THus avoiding any necessary circuit design.

Why don’t you write your own software?

Or, if you want to make your own programmer, you could buy the TI one, trace the circuit, and build your own copy of it.

Leon

Yer, i suppose i will have to as i doubt that there would be a software emulator for this. Well, in that case, how hard would it be to emulatre the Spi Bi Wire protocol. From what ive read it multiplexes the signal to allow for it to use only 2 wires. Any where to get specifics for the Spi Bi Wire protocol?

Try the Microchip web site. They might not have published them, though.

You are probably in for several weeks of work, even if you find the details, as you don’t seem to have much experience of that sort of thing. It really would be much easier just to spend a few $.

Leon

Mr Awsome,

I just want to put my comments in brackets.

Even if You can write a software to implement the SpyBy wire protocol using any two pins of Your PC and it can be used for programming the device, wouldn’t You need a debugging feature? If yes, then You will have an even more challenging obstacle, to make Your software to be able to pretend itself as a general programmer, debugger interface well known and supported by Your environment (IAR, Rowley, whatever).

I think programming skills and experience is worth nothing without the necessary documentation, specs, … and AFAIK this information is not commonly available.

Freescale is an other story, they “support” several non-profit projects to build cheap programmer/debugger boards for theirs MCUs, but till that time I did not hear about any similar project in case of other manufacturers including TI.

There are projects for building cheap JTAG interfaces for parallel port or USB, but there is always the same problem You are facing, support from the side of development environments.

Anyway, I wish You good luck and endurance.

BR,

Blaise

Ok thx, I see