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[Phill]

Hi Tom, thanks for cleaning my post up....

Yes, I changed the pin mapping as shown on the pin mapping code on my previous post. Having revisited GigiG's site I cannot discount the fact that there might be some faulty pins on the mega. I will look at this tonight and see what I can determine, and perhaps use two different ones instead of 2 and 3.

The results are consistent on both

multi-meter and scope.

i'll also try the manual slews you have suggested at the same time and report back.

Thanks

[Phill]

Hi Tom,

I've re-checked all and it is clear that my attempt to recompile the mega hex is at fault. I've been using IDE 1.6.8 which produces build15fa645bf85df0b6ef71985362896bb6.tmp but I seem to be getting lost after this.

Regards

[TCWORLD]

I don't think it compiles properly on the latest version of the IDE. You will need either Arduino IDE 1.0.x, or UECIDE.

[Phill]

Thanks Tom,

I think I've read this somewhere before. If I remember correctly I had to do just this on my nano TinyAltimeter as it would only upload a sketch from 1.0.6. I may still have that on my wife's laptop.

Thanks again.

[Phill]

Tom,

I was never cut out to be a software, "wizz kid" but I am a dab hand with the soldering iron.

I couldn't get the pinmapping to change and I haven't got time at the moment to learn UECIDE. So I dropped back to my old hardware hacking skills and did a cut and "paste" on the breakout-board. Not pretty and my Dad would have a fit if he saw it, but, horrible, as it looks it does work!

Sidereal at 1 rev per 48 seconds as I'd hoped for. My 290 oz motors are a bit "clunky" on full stepping and I can only get 100X on the goto (12V into an 8V motor) before it looses sync but that's still 25% better than before.

Now I have a platform to work from I'll start looking in to how to speed things up and smooth things out. I appreciate that's probably a change of motors or gearing. I'll open a new thread soon to discuss this.

In the meantime many thanks for the great design and hard work.

Phill

[TCWORLD]

You could try selecting 1/16th stepping. Makes the "IVal" a little low, but it may give you a little more speed as the motors will be half-stepping instead of full-stepping.

[Phill]

Hi Tom, thanks for the advice.

I tried 16uS which makes the tracking quieter but doesn't have a significant impact on speed. I think initially the best way forward is to investigate other motors.

Kind regards

[Phill]

Phill's silly question of the week!

Whilst waiting for the new motors to arrive, I've been building a new proto-board. I've based it on this version.

http://www.ebay.es/itm/1-PCB-Shield-Arduino-Mega-2560-R3-FADIMEGA-368P-Protoboard-genuino-/162099883360? Change out of €3 can't be bad!

I have to say this is a great board. There are no header pins as standard, which I preferred, as I wanted to fit tall ones. The holes are grouped sensibly, especially for motor boards, and there are rows/columns of GND and VCC holes. For an old pensioner like me I especially appreciated that GND is square, VCC is octagonal and group holes are round. An added bonus is that the holes can be soldered from both sided, making it easy to run on the underside.

Now the question! Tom, I appreciate that there are a few pins that cannot be used, but I wondered why you chose the resets to be on A0 and A1? To keep my board tidy is there any reason why I couldn't use 9 and 14?

This is giving me so much enjoyment. It's almost going to be a disappointment when it's fully finished. 

[TCWORLD]

I don't think there was any reason in particular to be honest. I'm actually not sure I remember when the pin mappings for the Arduino Mega version were picked - and to be honest for both the Mega and 162 versions, if I could go back and change the pin assignments, I would.

Tom.

[Phill]

That was quick!!

Thanks Tom, I just wanted to be sure. I already have enough "trophy" 4988s and 8825s