Backup / Reverse light output from Mshift?

A forum for discussing applications and implementations of the MegaShift transmission controller code for the GPIO from B&G. This can control up to 8-speeds and 6 shift solenoids (plus a 16x9 table for controlling a PWM line pressure valve). It has manual and fully automatic modes (16x9 load x speed table), with under and over rev-limit protection, and full data logging of all inputs and outputs (among many other abilities). A TransStim to test your completed board is also available.
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Philip Lochner
Posts: 34
Joined: Thu Mar 08, 2012 9:00 am

Backup / Reverse light output from Mshift?

Post by Philip Lochner »

Is it possible to configure a spare port on Mshift to switch the backup/reverse lights on (via a relay)? I want to the output to go low (or high) only when the transmission is in Reverse. My car does not have a mechanical switch for this purpose and I don't fancy fabricating one...
Best regards
Philip
'80 Jaguar XJS 5.3L V12 = MS-2
'74 Jensen Interceptor Mk3 440 V8 = MS-2 + GPIO (GM 4L60e)
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: Backup / Reverse light output from Mshift?

Post by Bernard Fife »

Phil,

You *should* be able use the 'current gear' mode for the spare ports. You would set the conditions all to "no condition", except for the "gear threshold", which you would set to "equal" -1.

However, I just tried this on my bench and it doesn't work. There are a few issues. First, the INI won't accept negative values for the gear, so that will need an adjustment. But even when non-negative gears are selected the PWM% doesn't appear to respond properly, so that needs fixing too.

I'll look in the code and post back here when I have a tentative solution.

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
Bernard Fife
Posts: 1696
Joined: Fri Apr 04, 2008 1:28 pm

Re: Backup / Reverse light output from Mshift?

Post by Bernard Fife »

Phil,

Actually, thinking about this just a bit more, I realize the easiest way to do this is to make one of the unused spare ports a "shift solenoid". Then have that output "off" in all gears except reverse where it should be "ON". Set the PWM% table for the spare port so that it is filled with all 100% (this will be the "ON" PWM percentage, and it will vary otherwise).

Lance.
"Never wrestle with pigs. You both get dirty and the pig likes it." - George Bernard Shaw
Philip Lochner
Posts: 34
Joined: Thu Mar 08, 2012 9:00 am

Re: Backup / Reverse light output from Mshift?

Post by Philip Lochner »

Lance wrote:Phil,

Actually, thinking about this just a bit more, I realize the easiest way to do this is to make one of the unused spare ports a "shift solenoid". Then have that output "off" in all gears except reverse where it should be "ON". Set the PWM% table for the spare port so that it is filled with all 100% (this will be the "ON" PWM percentage, and it will vary otherwise).

Lance.
Excellent!! I've just come to the realisation today that I've been burnt (quite literally) by a local product. My gut feel was to go with GPIO based on all my MS experience but the price is now 3 times more than the local product, compliments of our currency which is now going "Zimbabwe" on us.
Best regards
Philip
'80 Jaguar XJS 5.3L V12 = MS-2
'74 Jensen Interceptor Mk3 440 V8 = MS-2 + GPIO (GM 4L60e)
Philip Lochner
Posts: 34
Joined: Thu Mar 08, 2012 9:00 am

Re: Backup / Reverse light output from Mshift?

Post by Philip Lochner »

I decided that I was not going to implement the 4 LEDS and used one of them to control the reverse light relay.
Best regards
Philip
'80 Jaguar XJS 5.3L V12 = MS-2
'74 Jensen Interceptor Mk3 440 V8 = MS-2 + GPIO (GM 4L60e)
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