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Thread: Open Hardware COP controller

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Posts: 11-20 of 75
2016-06-14 12:06:04
#11
Originally Posted by Storm88000
You must be an electrician, no? Good work. (Not that I understand most of it)


Would that make a petroleum engineer a plumber?
2016-06-14 13:07:37
#12
The trick to making the circuit work was to have the controller sync with the ECU timing. From a discrete logic point of view, this was kind of difficult to figure out. I had to treat the signals as if they were being written to a register, without and actual register. Using a shift register would work, but would add more components to the design. Here is the timing tables to explain how the sync circuit works. To reset, I had to count the 360 tick mark only when the cylinder position window was open. Two inputs equals one output. The output is used to reset the sequencer.

https://drive.google.com/open?id=0B53t_ZvnBllXd1p5X0NZTnk5Y2c
https://drive.google.com/open?id=0B53t_ZvnBllXVXYzMnVQcGF5MjQ
2016-06-14 19:24:52
#13
Originally Posted by 1fastser
Originally Posted by Storm88000
You must be an electrician, no? Good work. (Not that I understand most of it)


Would that make a petroleum engineer a plumber?


Nah the top field takes precedence. So he'd be an engineer who may understand a trade such as plumbing
2016-06-14 21:17:56
#14
Originally Posted by Storm88000
Originally Posted by 1fastser
Originally Posted by Storm88000
You must be an electrician, no? Good work. (Not that I understand most of it)


Would that make a petroleum engineer a plumber?


Nah the top field takes precedence. So he'd be an engineer who may understand a trade such as plumbing


...like an electrical engineer who may understand eletricity? Clearly you didn't get it, lol.
2016-06-14 21:23:08
#15
Hey your build link isn't working!
2016-06-15 01:00:15
#16
The windows I refer to in my last post are on the cam trigger wheel. Three of the same size and one large one. The large window is where the binary count comes from. There are 9 "bits", not technically, within the window that can be counted, 8 was all I needed. When the circuit sees the large window it will count the 360 tick marks. That's the secret to all this. Sync the large window with one, and use a sequence to push the binary count.
2016-06-15 11:07:10
#17
BCD is essentially binary, just arranged differently to represent decimals. In binary world we start counting at 0 so technically I had to count 9 in order to get a bcd output of 8. What made this the number to use was that 1 in 1000 is the MSB( most significant bit) and if you are familiar with binary you know that this bit only pops up when the count hits 8. So this was the magic number. Connecting the MSB to the sequencer reset allowed the sequencer to be reset whenever the large window opened and the binary to BCD counted to 8. And since the large window represent the last of the firing order (firing order 1*3*4*2), we just reset back to 1.
2016-06-15 11:28:40
#18
Luckily since I needed 2 binary counters the 4520 binary counter has two counters built in. One counter is used for the reset counter while the other is used for the cylinder position sequencer. The reset counter is reset every time the position window was "low". High being the window is open and the counter is seeing 5v, low being the space between windows and the circuit sees 0v. The sequencer was only reset when the reset circuit counted the 9 bits. So with one component I was able to make the sync and sequence decode the cam trigger wheel. But more was involved with getting it to interface with the car.
2016-06-15 12:08:52
#19
This sounds reasonably easy but a wrench was thrown into the mix. The 4520 uses a 5v reset, so the signal from the cam trigger could not be used, not in its current state anyways. I had to invert the signal using a logic inverter. There are numerous ways to do this and initially I chose to use an IC (integrated circuit). This was a catch 22 though, the IC is large and I only needed 2 inverters and the IC had 4. So half the IC was sitting there wasting space. For the longest time I had used this IC until we started messing around with npn and pnp transistors in class. This lead me to understand that I can control these signals with 2 transistors. If anyone has ever seen a transistor, you under stand the size difference between 2 transistors vs a 14 pin through hole IC.

http://www.nxp.com/documents/data_sheet/HEF4520B.pdf
Last edited by ebinkerd on 2016-06-15 at 12-14-29.
2016-06-15 13:48:55
#20
Great work!
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