Memory dump of ECU

[Dessertrunner]

How come I didn't think of that Tom, must be your smarter then me. Here are a number of pages that would be of use.
Tony

[Dessertrunner]

and more pages. By the way don't try to change to less sensors as the engine won't rev past 5,000 if you do.
Tony

[Nomake Wan]

Thought I would mention... I still don't have the "92 problem" board wired up to my USB-TTL adapter, but I was at work the other day and was talking about printers when the subject of my old ThinkPad and using it for ECU tuning came up. Normally that topic dies quick with a "Wow, computer with a car!" thing since the other person didn't get it, but this guy went, "Oh cool, I build sand cars and we've got lots of Subies. Lots of 2.0s but we have some EZ30s too." And so I ended up spending an hour just talking about the tuning they do, the hardware they use, stuff like that.

When he gets some free time he'll invite me over to the shop to try out his adapter. From what I gathered by talking with him, it's not like the ones we have, but it's also not a real SSM. I'm curious what exactly the adapter is, and if it'll work with any of our software. Or if their software will work with our motor!

When I stop by I'll see what I can do and post back. If there's anything specific you guys want tested out, let me know before hand so I'll know what to get ready.

[Dessertrunner]

Calum anymore update on were we are heading with this

[b3lha]

I've been looking at ways of getting updated software into the ECU. This is a long post, so if you don't want to read it all, read the paragraphs marked with yellow smileys.

I called in at "Power Engineering", one of the top engine tuning companies in the UK. They are only about a mile from my house. The guy said that the 27C1028 chips are no longer available and he recommended trying to find a memory adapter board on ebay. I was hoping he might have had something in stock, but no. Actually he said for older Imprezas and Legacies he replaces the ECU with an Apexi standalone unit because it's easier to work with and costs the customer less in the long run.

After a bit of searching I managed to find someone with a small stock of the obsolete 27C1028 EPROM chips and a fancy eprom programmer that can burn them. While this is a viable option, it's maybe not the best way to go. The blank chips are expensive and in short supply. I've also read that these 15+ year old chips are not very reliable, either having been sat on the shelf or previously used. It also means that any time I want to try something I would have to mail the chip to the guy and pay him to reload it.

Then I started looking into the memory adapters as used by LAN. These boards allow the ECU to use two 27C512 EPROMS instead of the 27C1028. The 27C512 EPROMS are cheap, easily available and can be burned with a $20 willem programmer from ebay.

I contacted the Scoobyecu guys who have a lovely picture of one on their website. The guy said he would see if he had a board lying around somewhere. I get the impression that they only made one batch of boards and most, if not all, are now gone. In fact, their website disappeared a few days ago.

I did actually find someone selling a memory board on ebay, but for £190 I think I'll pass.

So then I started wondering if it was possible to build a memory adapter board. I remember seeing pictures of one on Kashima's website. As luck would have it, the circuit diagram is on his website. But it's a complicated circuit, not something that can be made by threading wires through a plastic board, like the SSM connector circuit. Kashima used the wire-wrap method to make his, but I don't have his skills. What is needed is a proper printed circuit board. So I looked at ways of making a printed circuit board. It involves drawing the tracks on a copper coated board with a pen and then dipping the board in acid to remove the excess copper. But you have to have the acid at the right temperature and keep it in there for the right amount of time. Again, not something for an amateur to attempt.

I found a company called ExpressPCB. You download some software from their website and use it to draw your circuit layout. Then you send them the file and they will send you back three professionally made boards for just $51 + shipping. Then you just have to solder the 7 components to the board. Cheap and easy!

So I've taken Kashima's schematic and used the ExpressPCB software to produce a circuit board layout. Laying out a circuit board is hard to do without ending up in a mass of spaghetti wires crossing over each other. This is my 6th attempt and I'm finally happy with it. I am going to upload the file here and to my website so that anyone who wants memory adapter boards can download it and order some from ExpressPCB. I'll be ordering the first batch after pay day.

Now for some pretty pictures:
This is the complete circuit layout:


This is the top side:


This is the underside:


This is a link to download the file for ExpressPCB.
http://www.alcyone.org,uk/ssm/modify/new.pcb

So, that's another piece of the puzzle in place.

Phil.

[Calum]

Whats the dimensions of your board? I still don't have an SVX ecu, but I've got a EJ20 ecu and it would be handy if the board would physically fit in both. You've probably done this, but if you haven't print a 1:1 image of your board, cut it out, and check that it physically fits where your expecting it to. Something so simple can save you some real money.

Ooo... one other suggestion, I just noticed this, don't lay the board out for even/odd arrangement. Save yourself the trouble of having to split the bin everytime you make a change and go ahead and waste half of each chip and set the board up for the same image on both chips (you've got the space to waste with 27SF512 chips). To do this just pull the A0 of what you've got designated as your even chip low, and the A0 of the odd chip high (you can tie them directly to gnd and +5V), and bump each of the address lines up one position (so A1 now goes to A1, etc). So each chip only gets half of its data read, but because your using a 27SF512 instead of the 256 its no big deal. Actually because the ECU is only using the top half of the memory space you really have the room to spare with the 256s anyway.

I would add bypass caps on the roms too, it doesn't cost you anything to do that.

Edit- whats going on with the A0? Why are you passing that through to the 27SF512s A0? Take a look at Kashima's schematic- althought he's latching it with one of the '573s he doesn't actually pass it to the '256s. He passes A1 to the roms A0, not A0 to A0. When the ECU reads from memory it always expects the even bytes to appear in the lower half of the data bus, and the odd bytes in the upper. So if you pass A0 your going to flipped flopper that arrangement unless when you burn the chips you double each byte (so on the even chip the same byte is read whether A0 is high or low, and the same for the odd chip). You could set your '512s to still work correctly with that, but thats complicated.

[svxistentialist]

That looks excellent Phil.

So you have not been idle in the interim like we all thought!

[TomsSVX]

I have a couple Stock ROM upgrade chips around here... Using them, there is no need to have a board made. They are erasable and re-writable... this may help us program chips for the stock ECU... Problem that still has me weary of using the stock ECU, it pulls timing when it doesn't really need to... How are we going to overcome this issue??

Tom

[b3lha]

Originally Posted by Calum

Edit- whats going on with the A0? Why are you passing that through to the 27SF512s A0? Take a look at Kashima's schematic- althought he's latching it with one of the '573s he doesn't actually pass it to the '256s. He passes A1 to the roms A0, not A0 to A0. When the ECU reads from memory it always expects the even bytes to appear in the lower half of the data bus, and the odd bytes in the upper. So if you pass A0 your going to flipped flopper that arrangement unless when you burn the chips you double each byte (so on the even chip the same byte is read whether A0 is high or low, and the same for the odd chip). You could set your '512s to still work correctly with that, but thats complicated.

You're right. I've stuffed it up. I did actually connect them correctly on my early attempts but then I got confused somewhere along the line. I'm glad you noticed before I placed the order. I'll fix it up tonight.

Originally Posted by Calum

Whats the dimensions of your board? I still don't have an SVX ecu, but I've got a EJ20 ecu and it would be handy if the board would physically fit in both. You've probably done this, but if you haven't print a 1:1 image of your board, cut it out, and check that it physically fits where your expecting it to. Something so simple can save you some real money.

The board is 3.8 x 2.5 inches. I measured the space inside the ECU and the position of the 1028 before I started and I left a some space around the edge of the board just in case it needed a little trim. I'll do a print out as you suggest to double check my measurements. From pictures, I think the early EJ20 ECU is the same hardware as ours, so it should fit both.

Originally Posted by Calum

Ooo... one other suggestion, I just noticed this, don't lay the board out for even/odd arrangement. Save yourself the trouble of having to split the bin everytime you make a change and go ahead and waste half of each chip and set the board up for the same image on both chips (you've got the space to waste with 27SF512 chips). To do this just pull the A0 of what you've got designated as your even chip low, and the A0 of the odd chip high (you can tie them directly to gnd and +5V), and bump each of the address lines up one position (so A1 now goes to A1, etc). So each chip only gets half of its data read, but because your using a 27SF512 instead of the 256 its no big deal. Actually because the ECU is only using the top half of the memory space you really have the room to spare with the 256s anyway.

I would add bypass caps on the roms too, it doesn't cost you anything to do that.

Those are both good suggestions and I will incorporate them into the design tonight. Thanks for your continued interest and advice.

Phil.

[b3lha]

Originally Posted by TomsSVX

I have a couple Stock ROM upgrade chips around here... Using them, there is no need to have a board made. They are erasable and re-writable... this may help us program chips for the stock ECU...

That's true. Do you have a suitable eprom programmer? The cheapo $20 programmers don't support that chip because it uses the same set of pins to read the address in and the data out. You need a fancy high-end eprom programmer that costs maybe 10 times as much.

Originally Posted by TomsSVX

Problem that still has me weary of using the stock ECU, it pulls timing when it doesn't really need to... How are we going to overcome this issue??

I need to figure out how the ECU calculates the timing. Then I can tell you exactly what input conditions cause it to pull the timing. Then we can change the thresholds as necessary to stop the timing being pulled in your specific application.

[TomsSVX]

I do not have a programmer but I would love to send them to whoever could use them. I was going to buy a good reader/writer a while back when UpNorth was still around and helping me

Its not just the s/c engines pulling timing, stock engines pull unnecessary timing as well, esp in the top end.

Tom

[Dessertrunner]

Nice work Phil it looks like you are getting there may be a few of us should send you some cash to help wiht the costs you are incurring if we all sent $100 or so it will add up.
Calum send me your mailing address I will try to send you a JDM ECU and I will also hunt around for a harness to get you going. Don't you need the full car and engine harness with all the sensors. Problem there is the sensors are difficult to spare.
Tony

[b3lha]

I can't take any financial donations. This is a hobby project and at the moment I can work on it as and when I get time, or just give up completely if I get bored with it. If I take money from people then I'll feel obligated to make progress and produce results. Besides which, It's not just me working on this now. There are lots of other people making valuable contributions of time and skills to the project and increasing our communal knowledge base.

Anyway. Something else I've been meaning to post for a while.

I was originially thinking that the solder tags on the TCU board were for an EPROM upgrade and that maybe the TCU used the same type of EPROM chip as the ECU. Now I think I was wrong about that, like so many other things. The wiring on the TCU board does not match the 27C1028 pinout. There are wires going to pins that as designated as "no connection" on the 27C1028 datasheet. In addition there is no obvious resistor to cut to enable the upgrade chip like there is on the ECU.

The stock EPROM on the TCU is a small surface mount 27C256. The solder tags seem to be wired the same as the stock ROM. I think maybe the idea was during the manufacturing of this board they could choose to either use a surface mount EPROM or a DIP-28 style EPROM interchangably.

So, my latest theory is that in order to upgrade the TCU, you have to use a DIP-28 style 27C256 EPROM, and disable the surface mount EPROM. I'm not sure whether you have to unsolder it completely or whether cutting the "chip enable" pin will do the trick.

This is probably a good thing. The 27C256 is probably easier to get and program than the 27C1028 used in the ECU.

[nextse7en]

Agreed with Tom here,

If we could simply optimize fuel maps through midrange (ala stage 1) and find a way to up the threshold so that the ECU doesn't pull nearly as much timing (I think the japanese did this for drivability, smoothness reasons) I think we could come up with a simple chip that would increase HP on a totaly stock engine 30 or 40 HP.


You'll all be rich!


-Patrick

[TomsSVX]

Originally Posted by b3lha

I can't take any financial donations. This is a hobby project and at the moment I can work on it as and when I get time, or just give up completely if I get bored with it. If I take money from people then I'll feel obligated to make progress and produce results. Besides which, It's not just me working on this now. There are lots of other people making valuable contributions of time and skills to the project and increasing our communal knowledge base.

Anyway. Something else I've been meaning to post for a while.

I was originially thinking that the solder tags on the TCU board were for an EPROM upgrade and that maybe the TCU used the same type of EPROM chip as the ECU. Now I think I was wrong about that, like so many other things. The wiring on the TCU board does not match the 27C1028 pinout. There are wires going to pins that as designated as "no connection" on the 27C1028 datasheet. In addition there is no obvious resistor to cut to enable the upgrade chip like there is on the ECU.

The stock EPROM on the TCU is a small surface mount 27C256. The solder tags seem to be wired the same as the stock ROM. I think maybe the idea was during the manufacturing of this board they could choose to either use a surface mount EPROM or a DIP-28 style EPROM interchangably.

So, my latest theory is that in order to upgrade the TCU, you have to use a DIP-28 style 27C256 EPROM, and disable the surface mount EPROM. I'm not sure whether you have to unsolder it completely or whether cutting the "chip enable" pin will do the trick.

This is probably a good thing. The 27C256 is probably easier to get and program than the 27C1028 used in the ECU.

I took notice to that as well. The chip in the TCU could easily be removed and a programed chip soldered in... Nothing very complicated at all, which has blown my mind as to why no one has done it yet

Tom