First of all - my system is now at ver 3.2.1 and running very well. It sounds crisper and the tickover is improved - I'd guess that I had been suffering some interference previously.
I have one query about the dual map switch on the options port. In your new wiring diagram for the V3 board you show a changeover switch to go between 12v (via resistor) and earth. What happens when the switch is between positions and the options port voltage is floating? I expect it would OK, but it's a tiny concern.
Presuming that the options port doesn't need much current when switched to the 12v line, wouldn't it be better to use a higher-value resistor permanently wired from 12v to the port, and use the closed switch to pull it down to 0v?
This also has the benefit of switch availability - automotive switches are easier to find in on-off rather than changeover!
cheers,
David
Dual map switch wiring
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david jenkins
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that would certainly work as well- I've pointed out there are many ways of doing this. In the diagram I was targeting the least amount of external components- zero, in the case of the TPS unit- but agree, your proposal is slightly better for the MAP design.
In your approach, make sure you have the switch after the resistor, so you don't short circuit 12V.
That input is 'floating' in the very brief moment in-between the throw of the switch. The processor will likely see that as a logical 'zero' so, but is not guaranteed.
In your approach, make sure you have the switch after the resistor, so you don't short circuit 12V.
That input is 'floating' in the very brief moment in-between the throw of the switch. The processor will likely see that as a logical 'zero' so, but is not guaranteed.
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david jenkins
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- Joined: Tue Feb 14, 2006 2:14 pm
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