Is a simple logic analyzer possible?

[moonshadow 2]

Here's the state it's currently in. The code is for the mspgcc toolchain. The sensor is attached to 1.7 and ground.

 

It's moved on a little since my last post: the signals I am analysing are pulse width modulated, so all the 0s are the same width so I discard those samples; given that, 16 pulses' worth of input buffer is enough for the longest code the remote transmits, so I scrapped the logic that dealt with the buffer filling to reduce the time spent in the port ISR. Also since I am only reporting logic 1 pulse widths I no longer need to keep track of the idle time in main().

 

I now also have a 7-segment LED display connected to 1.3-1.5 via a 74HC595 shift register, and code to drive this is therefore also present.

[NJC 17]

@Everyone

Thanks for all the support. Things get quite stressful sometimes.

 

@Moonshadow

Very cool project. If you need any help with analog filters let me know, I am quickly becoming an expert on them lol.

 

@Everyone

So here's a cool project proposal for any of you who are not sure what to do next. Find the spec's for your remote, and build a remote with the MSP430. All you need to do is play around with some PWM on an IR LED. These things are cheap, you can find them at Radioshack still (I think), or even pull one out of an old remote that's laying around. Just remember to limit the current correctly so you don't blow the LED. Then you can add a microphone, battery power it, and have a clapper which changes the channel for you. It would require very few passive components to get it up and running. It would be perfect for a project with the EZ430 for those of you who have it. You can use the target board with a small button cell battery to last forever!

 

:-)

 

-NJC

 

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http://msp430launchpad.com

[Sean 1]

Just to add to NJC's project idea, IR light is visible to most digital cameras, so you can use that to verify it works if you solder an ir led in place.