DIYEFI.org Forum

Dan: I used the same circuit and part # for the opto protection as you had drawn for your Ravage project. I have very, very, little experience with opto-couplers, but after taking a quick look at the data sheet for this part, it looks like the load resistor has a very large impact on the bandwidth ...

A little bit of documenting. Even though it's almost exactly like the datasheet. Peter, I don't believe that you can use the D44VH10 as your injector driver as it doesn't appear to be a darlington transistor. The datasheet (from ON) specifies it as a "normal" NPN power transistor. It does...

Hey Fred, I know there was a discussion about this a while back, but can you summarize why such a "beefy" part is needed? Is there a list detailing what the source voltage and current requirements of the different ignition drives one might have to interface to? I think this information may...

Hey Andy, I think that the Digikey P/N for the optos should be "PS299-1A CT -ND" (unless of course you really wanted 3,500 of them : ). Note that I did not check the BOM throuroughly for this sort of stuff, I was looking to find the specs for the opto and just find it SO easy to select the...

One more little thing -
The schematic shows 22uF caps on the outputs of the regulator and the BOM calls out 47uF.

Freescale recommends that VDDA go to VDD (VDD is 5vdc-cpu on my schematics and VCC is the 5vdc-analog supply), see page 1297 of the Freescale MC9S12XDP512 Data Sheet, Rev 2.21... But I would like to know why you think it should go to VCC (5vdc-analog supply) :-) Ding Dong, I'm Wrong (Assumed that s...

Haven't passed out yet so - 11. You may want to consider connecting VDDA on the uC to VCC instead of VDD. 12. You may want to consider connecting the Check Engine Light sub-circuit to VDD instead of VCC (it really doesn't have much to do with the analog stuff). 13. Can you use a single 5V regulator ...

Hi Andy, 6. BOM calls out a crystal with 20pF load capacitors, but schematic and BOM indicate 18pF caps are being used (not sure of the impact). You will probably find that you cant get a nice 16MHz crystal that requires 22pF load caps. 18pF/12pF is probably a better choice for crystal availability....

6. BOM calls out a crystal with 20pF load capacitors, but schematic and BOM indicate 18pF caps are being used (not sure of the impact). 7. 10k resistors on the VR inputs are only a 1/4W per the BOM. Your call, but they may over-dissipate (see my comments in the thread you reference in your VR note)....

OK, Comments are in no particular order or importance, I'll just submit em as I think about em. 1. Damn Andy, you are one fast and furious designer : ) 2. I think that its GREAT that the individual Digikey part numbers on the BOM have embedded links to the parts, but it might be helpful to others if...