Jimstim 2.0 + cpu 2.0.4 weird Wheel wave

Building and using the Stimulator to test your Megasquirt

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Jimstim 2.0 + cpu 2.0.4 weird Wheel wave

Postby Magovit » Fri Mar 13, 2015 12:02 am

Recently my jimstim cpu 2.0.2 was burned out and start to get hot, soo i read about this on jbperf site and did the tests to get the correct diagnostic and the result is CPU FAULT.
I got two new cpu from DIYAUTOTUNE and they come with new firmware 2.0.4.
Installed the CPU and every goes good, no more hot cpu.
The first test i did was the wave format of wheel to start calibrate my MS2v3 but for my surprise the wave showed was different from the old cpu 2.0.2.

I would like to be oriented to get the correct wave format to produce the correct wave like on 2.0.2 firmware.
obs: No metters if i choose Hall or VR simulator, the wave remains the same. :o
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Re: Jimstim 2.0 + cpu 2.0.4 weird Wheel wave

Postby racingmini_mtl » Fri Mar 13, 2015 6:50 am

One thing is certain, that's not due to the CPU. The CPU can only switch between 0 and 3.3V so if you get something other than a square wave, that's due to other components. So you need to check the board and see where the signal goes wrong; use the schematics (on the web site) to follow the signal from the CPU to the connector. Also make sure it's not your scope or probe that is creating this.

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Re: Jimstim 2.0 + cpu 2.0.4 weird Wheel wave

Postby ebinkerd » Thu Apr 23, 2015 5:35 am

I think the problem you are having is the pull up resistors are not in place. As you are not connected to the MS, you need to install the jumpers in order to get the correct signal and provide the JimStim with external 5v power. I ran into a similar issue when I first assembled mine.
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