AVR based logic analyzer.

[skyrock]

I just found a problem with the $10 L.A.

The circuit uses a MAX243 chip but I couldn't find it anywhere. There's only MAX232 available. Do you think it can be replace with 232 in this circuit?

http://www.geocities.com/ted_rossin/Electronics/Pic/Pic.html#LogicAnalyzer

 

[3v0]

I just found a problem with the $10 L.A.

The circuit uses a MAX243 chip but I couldn't find it anywhere. There's only MAX232 available. Do you think it can be replace with 232 in this circuit?

http://www.geocities.com/ted_rossin/Electronics/Pic/Pic.html#LogicAnalyzer

Yes any chip that does RS232 level shifting will work. Just be sure to read the datasheet for the RS232 part you use to find out what size caps it uses if any.

Where do you live ? Need to know that to aid in finding parts. Have you checked the Octopart search engine.

 

[skyrock]

I live in a small town in malaysia. Doesn't have a wide range of supplies over here.

 

[3v0]

I live in a small town in malaysia. Doesn't have a wide range of supplies over here.

You may want to go to the user CP and fill in the location.

 

[skyrock]

i've build the simple L.A. in just a few days and it is working well. the little disappointment for me is that it doesn't have a software side buffer to save more data.

I figured even if the PIC doesn't have enough resource to store data in it, it could be done at PC side software to store down the data for later analysis. But there's no source code provided for PC side application, so nothing much can be done.

regards,
SKY

 

[3v0]

With LA you want FWD. Faster, Wider, Deeper. For more samples you want it to be deeper, more memory.

The author has provided the source code. Upgrade the design to use a chip with more memory and speed. A port to an 18F chip should not be hard.

If the author has provided source code for the PC side interface you could add code to decode SPI, I2C etc.

i've build the simple L.A. in just a few days and it is working well. the little disappointment for me is that it doesn't have a software side buffer to save more data.

I figured even if the PIC doesn't have enough resource to store data in it, it could be done at PC side software to store down the data for later analysis. But there's no source code provided for PC side application, so nothing much can be done.

regards,
SKY

 

[Sceadwian]

A logic analyzer using the PC's parallel port.

8 channels all that's need is a printer port and an OS that allows direct parallel port access. I think a Win98 machine would work best but I've gotten it to work with XP (with some timing glitches)

 

[Mikebits]

You can do it with win2K also. That is the OS I am running, and have P port routines somewhere. They are in vis basic though.

 

[ikalogic]

As far as i know, it will be always better to do the aquisition on a micro-controller or dsp before sending the data to the PC, (or send it in packets like in USB) because multi -tasking operating systems like window have, always had, and will allways (lol ) have difficulties to be precise with timing down to the micro seconds.

 

[3v0]

That is only true if the multi tasking is preemptive or time sliced. In the case of win98 once a driver gets control it must give it up voluntarily. That is one of the reasons it was so easy to crash the 98 with driver code.

At least that is the way I remember it

 

[Sceadwian]

There were definitly glitches in XP, if it were on 98 with no other software running and a minimal driver set it should be as fast as the processor can run it to a pretty fine accuracy.

 

[Ubergeek63]

You want to make it real? Like 18 channels at 150MHz?

Digi-Key - 296-12489-ND (Texas Instruments - SN74V293-10PZA)

 

[Sceadwian]

80 pin TQFP, yeah, right up the hobbyists alley.

 

[ikalogic]

I am building a logic analyser with the following criteria in mind:

1- Simple to build for average level hobyist
2- Uses few and cheap components (actually only 2 components: an AVR and a 232)
3- Able to do give the best results, given the two constraints above!

So, as Sceadwian says, yeah, it may not be in the scope of my project, but thanks anyway

 

[Sceadwian]

Ika, using Windows98 with a faster modern computer you will be able to blow the doors off a micro controller with logic analysis. Feed a good clock into it as well and you don't have to worry about timing issues, just quantization error, which you have to take into account for on a micro controller anyways. No components, free software just wire directly to a parallel port.

 

[Mikebits]

80 pin TQFP, yeah, right up the hobbyists alley.

lol. What is the distance between pins on one of those, a couple butt hairs?

 

[Ubergeek63]

Actually it is 0.5mm, I have soldered that and worse by hand on our production boards. I've even lifted adjacent pins and soldered mod wires to them.

**broken link removed**

Makes it real easy, or if you are more sure of your soldering technique:

**broken link removed**

That FIFO would make an 18 channel 150MHz analyzer simple. it runs continuously until 2^16 samples after the trigger event and any old USB peripheral micro can read the results out and send them to the PC.

 

[ikalogic]

I'm keeping you guys informed of the progress..

I think the hardware and micro-controller part is finished once and for all (just for this first version )

The software is almost done, a beta version is coming out soon. I still have to write a little help (maybe it'll be online on my website though..), and allow users to export bitmap screen shots, and save/open data for later analysis.

I've been testing it all the week-end and it was a lot of fun playing with my brand new logic analyzer! i've posted some screen-shots of one testing session..

I'm not sure if the first beta version will incorporate decoding UART/SPI/I2C data buses..

Waiting for your comments!

 

[3v0]

Looking good

 

[ikalogic]

A first version of the LA is finally finished

find all detail here:
**broken link removed**

EDIT: can anyone please download the SCNALOGIC software, and tell me if it is working on his OS, as it is made under VB and i didn't include the dependencies and VB runtimes, as they are too big...