TinyIOx Scanner and MicroSquirt cant "see" it

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racingmini_mtl
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by racingmini_mtl »

These are the 5V traces (approximately) and pads around the main 5V pad and that power the CPU (there are other traces and pads for the other chips but they should not be an issue at this point). Check what the resistance is between these and report what you find here.

Jean
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SethU
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by SethU »

I'm getting different readings depending on which probe I put in the 5v+. For instance, between A and B, with the red probe in A it reads 1.9 MOhm. Black probe in A reads 3.44 MOhm.

Results below are with the Red Probe on the first listed location. So, A to B, the red probe is on A.

A to B 1.9 MOhm and falling
A to C Same as above
A to D 69 kOhm
A to E 69.1 kOhm
A to F 68.7 kOhm

B to C 0.1 Ohm
B to D 3.3 MOhm
B to E 3.29 MOhm
B to F 3.29 MOhm

C to D 3.29 MOhm
C to E 3.29 M
C to F 3.30 M

D to E 0.1 Ohm
D to F 0.1 Ohm

E to F 0.1 Ohm
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by SethU »

I think I may have burned those traces. Is there an alternate place I can run power to?
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by racingmini_mtl »

Yeah, it does look like pad A is no longer connected to anything. The only places are the ones shown there. You could use pad B but you would have to run a wire from B to D.

Moreover, you will need to also run a wire to power the other chips because they also connect to pad A. The picture below shows 2 vias on the other side of the CPU which are connected to a trace that goes to pad A. You would need to connect pad B to one of these. You can check if you have continuity with the other 5V pads but I doubt because they go through pad A only (but on the back of the board so that may be different).

So to power everything, you need to connect 5V to pads B and D and one of the vias in the picture below. That's what pad A is suppose to do and it is the only connecting point for these 3.

Jean
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by SethU »

Soldered in jumpers from A to B & D. Traces on the back are fine. We have lift off! :yeah!: Thanks so much for the help Jean.

Next question, I've read that I shouldn't power the TinyIOx and it's additional sensors from the MicroSquirt Vref. If I power the TinyIOx with a 5v regulator, should I also power the sensors associated with the TinyIOx with the same power supply, or use the MicroSquirt's Vref for the sensors and separate the TinyIOx's Vref from it's power source?
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by racingmini_mtl »

Good to see you have it working. It is always nice to see your device on the port scanner output.

The Microsquirt power supply has a very limited excess capacity so it's not a good idea to use it to power the TinyIOx even though it doesn't drain a lot of current. So a dedicated 5V regulator is ideal and you will want to use it as the Vref supply for the TIOx. And unless you add more filtering to it to have a dedicated Vref, you can simply leave the standard TIOx connection between 5V and Vref (so there is no need to connect anything to the Vref pad).

I recommend going this way because the TIOx itself is not a noisy unit. The only reason you'd want a dedicated Vref is if you have many outputs (especially PWM outputs) which are directly connected to 5V and draw a significant current. If you do see a lot of noise on the ADC inputs then you may want to consider having a separate Vref. In that case, you'd connect Vref to the Vref pad and cut the trace between the 2 pads of the solder jumper (pad D and the one besides it).

Jean
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by SethU »

I intend on using the TinyIOx for 4 pressure sensors,3 temperature sensors, and I'm not positive about the remaining ADC. Not sure if I'll be able to utilize any of the timer channels. I'll start another thread about the possible uses for those.

I'm looking for something small, compact, and low profile. Would this be an appropriate 5v regulator for my intentions?
http://www.digikey.com/product-detail/e ... ND/2280328

Or do you have a preferred component you'd recommend?
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by racingmini_mtl »

That's a fine choice if you're going to be making your own board because this is a surface mount device that requires a board with the correct footprint and heat sink area. If you will only use a proto board or the proto area, you will need to use a larger through hole package such as the TO-220 and you can then use the LM2940 which is what is used on the MS V3.0 board (or the equivalent). You can then use the case as the heat sink.

Jean
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by SethU »

Looks like the TO-220 package might be the way to go. I'm assembling the sensors circuits on the proto area with SMD components and I'm going to mount it to the back of the TinyIOx on a couple stand-off's providing a little space between the two boards to run connecting wires. My intention is to encapsulate the whole package in potting resin. I have very little experience with this stuff, but I imagine that would provide enough surface area to dissipate heat, unless potting resin doesn't transfer heat well enough. Do you foresee any issues with this plan?
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by racingmini_mtl »

For the voltage regulator, you definitely need a heat sink. So if you screw it to the case that will be fine with or without potting it. For the inputs, there won't be any issue with potting but if you have some outputs, you need to consider how much current they draw. Potting resin is not a good heat conductor unless you use one that is designed for heat conduction.

Jean
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Re: TinyIOx Scanner and MicroSquirt cant "see" it

Post by SethU »

It's being used with a MicroSquirt... Plastic case and won't fit anyway. It's going to have to be externally wired, as a standalone package. I'll have to figure out some heat sinking solution. Perhaps I'll put the regulator external to the potted TinyIOx. Thank you for the feedback Jean.

Started another thread for all my other questions.
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