A simple I2C master implementation on the MSP430 | Hacker News Reader

A simple I2C master implementation on the MSP430

simplyembedded.org

It's amazing how (comparatively) convoluted I2C is on platforms without the Wire library support you see on Atmel platforms.

That's not to say that such platforms are bad (MSP430 has it's advantages and disadvantages depending on what you want to do with it), but more of a testament to the Wire library.

It's not too surprising that a high-level I2C abstraction looks less convoluted than a register-level I2C driver.

Here's the equivalent code for the Atmel peripheral: https://github.com/arduino/Arduino/blob/master/hardware/ardu...

Getting a 503 error for the entire site...

Just went to find the page of internet archive:

    web.archive.org has been blocked by Sky Broadband Shield, which lets you choose the websites that can be seen in your home.

I hate ISPs. If someone could update the link, that would be grand!

Perhaps this might do the trick?

http://webcache.googleusercontent.com/search?q=cache:gmd3HGA...

Change your DNS servers?

503 is "Service unavailable" where the service is related to the web server, not DNS.

https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#5xx_...

Yes, but this is probably served by the ISP's servers, into which traffic was redirected by the ISP's dishonest DNS.

This is much easier to implement than fully intercepting every HTTP connection, and this is what most ISPs go with.

Would that work? Sky Broadband Shield is a service which blocks adult content (and for some bizarre reason archive.org?) Would changing your DNS server make a difference? Your ISP should still be aware of what IP the content is coming from.

They actually override all DNS lookups if I remember rightly. It's not my connection, so I can't change that fact - I just think it's a naughty thing to do.

But it's a bit off topic!

Link works fine for me now. In case it stops working again, here's a snapshot hosted at another archival site: http://archive.is/cRT4A

If someone is interested in a simple and straightforward implementation of I2C on MSP430 with the USI module (the simpler serial module found on cheap low-end chips), I wrote a library a couple of years back, because I couldn't find anything I'd be happy with: https://github.com/jwr/msp430_usi_i2c

The code is also fully interrupt-driven, which is important for low-power applications.

This is much cleaner than TI's reference implementation.

It may be so, but it doesn't implement an interrupt solution, which is a really bad way to program a microcontroller.

Also I found these types particularly amusing. None of that code can be copy pasted without editing:

  while ((err == 0) &amp;amp;&amp;amp; (nbytes &amp;gt; 0))

But since it doesn't support interrupts, I think not being able to copy paste this code is generally a good thing.

I'd tend to agree! But for those of us totally unfamiliar with how I2C works, and barely familiar with embedded dev at all, a somewhat gentler introduction to the relevant concepts, that requires close experience with fewer priors than TI's reference example, is no bad thing to have.

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