CAS pull-ups MS3X

MikeSr. · 11-01-2021, 12:25 PM

Looking at the hardware manual for MS3X, I see the CAS inputs- MS3X cam, MS3 crank. These are “hall sensor open collector”, so will need pull-up resistors. Unsure of where physically to put the resistors-JP7? In the harness from input to ground?

Harlard · 11-01-2021, 12:42 PM

Is it an assembled v3.57 board?

MikeSr. · 11-01-2021, 12:51 PM

Yes- using Yoshifab CAS

Harlard · 11-01-2021, 12:57 PM

You don't need a pull-up, then. Just make sure there's a jumper on JP3, JP7 and nothing on JP8.

MikeSr. · 11-01-2021, 01:16 PM

Just trying to sort out after reading the hardware manual and the CAS thread on Tb- much of which disappeared with Gross Polluter’s departure.
The DIY site discussion of Megasquirt-III with MS3X says to set the main board for VR input(?) - I thought the VR circuits are not used.
Quote DIY-“ On a V3.57, put JO1 in the 1-2 position and J1 in the 3-4 position.”
Since I have not opened the box yet, I have no idea what this means or what it applies to hall sensor open collector.
“For a pull-up on the CMP input, make sure JP7 is in place on the MS3X.”
Is JP7 a simple jumper and the 1K is enabled by this? Or is JP7 jumped with a 1K?
“ The CKP also needs pull-up. You can put this in place internally or externally. For an external, run a
1K resistor from pin 26 to pin 24 on the main board.
For an internal pull up on a V3.57 board, solder a 1K resistor to R 57”
Just a little confusing to me

MikeSr. · 11-01-2021, 01:20 PM

Quote:

Originally Posted by Harlard

You don't need a pull-up, then. Just make sure there's a jumper on JP3, JP7 and nothing on JP8.

Thanks, Harold

linuxman51 · 11-01-2021, 01:55 PM

I always used 1k pullups built into the harness. don't be surprised if it acts odd running the input into the VR conditioner.

MikeSr. · 11-01-2021, 02:05 PM

Quote:

Originally Posted by linuxman51

I always used 1k pullups built into the harness. don't be surprised if it acts odd running the input into the VR conditioner.

I saw you said not to use VR conditioner in the thread- if I use cam to MS3X input and crank to Main board input with 1K to ground on each- would that work?

linuxman51 · 11-01-2021, 02:12 PM

the ms3x cam input is a vr conditioner as well. I ended up getting an external MAX9926 based conditioner for mine (same deal as the ms3pro and microsquirt rpm inputs). still need the pullups, but you'd wire/solder the outputs directly to the pin inputs on the processor.

the problem I always had with the old vr conditioners was some sort of signal drift (for lack of a better description), timing was unstable at higher rpms and the car seemed 'off' all the time until I made the change, then it started behaving. I've actually run into that a couple of times on a couple different cars, this was the safest (electronics wise) way I found to get around it.

Harlard · 11-01-2021, 02:39 PM

Interesting. I figured that drift was a function of timing belt stretch.

This makes me want a Maxxecu even more now...

MikeSr. · 11-01-2021, 03:58 PM

Oh, jeez- I think I screwed the pooch-I removed the two screws holding the black sensor to flip the wheel .
Time for a new CAS?
These:

AndrewNance · 11-01-2021, 04:01 PM

I did that on mine too before reading that you aren’t supposed to but it didn’t ruin anything.

MikeSr. · 11-01-2021, 04:05 PM

Good- thought I broke it

11-01-2021, 12:25 PM	#1
MikeSr. What, me worry? Join Date: May 2003 Location: Acworth, Ga. USA	CAS pull-ups MS3X Looking at the hardware manual for MS3X, I see the CAS inputs- MS3X cam, MS3 crank. These are “hall sensor open collector”, so will need pull-up resistors. Unsure of where physically to put the resistors-JP7? In the harness from input to ground? __________________ I coulda had a V8!

11-01-2021, 12:57 PM	#4
Harlard Hurlurd?Harland?Bueller? Join Date: May 2007 Location: PDX	You don't need a pull-up, then. Just make sure there's a jumper on JP3, JP7 and nothing on JP8. Last edited by Harlard; 11-01-2021 at 01:06 PM..

11-01-2021, 01:55 PM	#7
linuxman51 BRANDSCHUTZVORSCHRIFTEN! Join Date: Dec 2002 Location: mont, AL	I always used 1k pullups built into the harness. don't be surprised if it acts odd running the input into the VR conditioner. __________________ "They bum rushed them in their own crib, they drank all their beer, they partied with their ladies and they left with the trophy" Now with in-house Dyno tuning! Megasquirt Tuning!

11-01-2021, 04:01 PM	#12
AndrewNance Amateur hour! Join Date: Oct 2011 Location: Winston-Salem, NC	I did that on mine too before reading that you aren’t supposed to but it didn’t ruin anything. __________________ '67 122 - b230, t5, 8.8 Feedback

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11-01-2021, 12:51 PM	#3
MikeSr. What, me worry? Join Date: May 2003 Location: Acworth, Ga. USA	Yes- using Yoshifab CAS

11-01-2021, 01:16 PM	#5
MikeSr. What, me worry? Join Date: May 2003 Location: Acworth, Ga. USA	Just trying to sort out after reading the hardware manual and the CAS thread on Tb- much of which disappeared with Gross Polluter’s departure. The DIY site discussion of Megasquirt-III with MS3X says to set the main board for VR input(?) - I thought the VR circuits are not used. Quote DIY-“ On a V3.57, put JO1 in the 1-2 position and J1 in the 3-4 position.” Since I have not opened the box yet, I have no idea what this means or what it applies to hall sensor open collector. “For a pull-up on the CMP input, make sure JP7 is in place on the MS3X.” Is JP7 a simple jumper and the 1K is enabled by this? Or is JP7 jumped with a 1K? “ The CKP also needs pull-up. You can put this in place internally or externally. For an external, run a 1K resistor from pin 26 to pin 24 on the main board. For an internal pull up on a V3.57 board, solder a 1K resistor to R 57” Just a little confusing to me

11-01-2021, 02:12 PM	#9
linuxman51 BRANDSCHUTZVORSCHRIFTEN! Join Date: Dec 2002 Location: mont, AL	the ms3x cam input is a vr conditioner as well. I ended up getting an external MAX9926 based conditioner for mine (same deal as the ms3pro and microsquirt rpm inputs). still need the pullups, but you'd wire/solder the outputs directly to the pin inputs on the processor. the problem I always had with the old vr conditioners was some sort of signal drift (for lack of a better description), timing was unstable at higher rpms and the car seemed 'off' all the time until I made the change, then it started behaving. I've actually run into that a couple of times on a couple different cars, this was the safest (electronics wise) way I found to get around it.

11-01-2021, 02:39 PM	#10
Harlard Hurlurd?Harland?Bueller? Join Date: May 2007 Location: PDX	Interesting. I figured that drift was a function of timing belt stretch. This makes me want a Maxxecu even more now...

11-01-2021, 04:05 PM	#13
MikeSr. What, me worry? Join Date: May 2003 Location: Acworth, Ga. USA	Good- thought I broke it