Parallax Basic Stamp

User topics relating to hardware that interfaces PCs to ECUs

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Parallax Basic Stamp

Postby Hawke » Fri Jan 13, 2006 6:19 am

Anyone ever try to get the Parallax Basic Stamp to work with the SSM protocol? Here is the one that I'm trying to get working:

http://www.parallax.com/detail.asp?product_id=BS2-IC

Haven't had any luck so far. If I use portmon while I have the setup connected to the serial port on my computer it looks like I'm sending out the correct information for an ECU init. If I send that info back to the device, it then displays it on an LCD screen I have connected. However, from what I can tell, it doesn't work at all when hooked up to the car. I'm trying to make a device that I can monitor and display some of the info IAM, Knock correction, boost etc without the need for a laptop to be connected all the time. Right now I'm using my accesport cable that connects to this:

http://www.parallax.com/detail.asp?product_id=27120

which has the chip on it.

Is there a constant stream of data over the port on the car? or only when info is requested? The other issue I see is the Vpp is 5v instead of 12v, but from what I can tell, that should only affect sending the data, correct?
Hawke
 
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Postby cdvma » Fri Jan 13, 2006 3:28 pm

You don't have to init. You also only get data when requested, it does not stream. DO NOT hook up a 5v board to a 12v power source, you WILL blow it up. RS-232 does not vary with the power, its got its own voltage levels as part of the protocol.
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Postby Spiider » Fri Jan 13, 2006 6:26 pm

I do some work with Microchip's PIC microcontrollers. They are a lot more flexible and less expensive than the Basic stamp stuff.

If you are programming directly in assembly the learning curve is steep, but worthwhile.
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Postby Hawke » Sun Jan 15, 2006 3:39 pm

Thanks for the info on the line basically being dead unless info is requested. The GM vechicles that I have worked with have a constant stream of info on the bus with all the modules talking to one another, this must be different. I'll have to try to see if I can get the Vpp up to 12V and try to request the info again to see if that works.

I just had the stamp laying around so that's what I went with. It is fairly limited with the serial port communications. If I don't get this to work and haven't given up I'll have to look into the PIC controllers.
Hawke
 
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Postby intrawrx » Sun Jan 15, 2006 10:55 pm

While we are on the subject of microcontrollers, i was thinking of building an AVR project where we could use SSM to init the ecu and then fit in some data into RAM for use as maps.

Hook up an LCD module... cool would that be! :)
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