sr5guy

My theory is that a better understanding of how the ECU is set up in hardware would lead to it being much easier to understand how the software operates it. My current project is to document all of the on-board IC components, then hopefully, with some help from other board members, make some basic schematic and block diagrams.

This is what I have figured out so far, if there is an interest I can imagemap this picture with links to download the PDF files.

__________________
The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

No, really, stop asking


The Legend Garage

 

sr5guy

__________________
The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

No, really, stop asking


The Legend Garage

sr5guy

I need your help in identifying: IC402, IC501, IC804 & IC700 (all Matsushita)

Here are links to download individual PDF datasheets for the IC's.

Hitachi 6435328CP10; H8/532 MCU:
http://other.ditcorp.com/legend/datasheet.pdf

Matsushita 27C256 ROM Chip:
http://pdf1.alldatasheet.com/datashe...27C256-10.html
There is a much better pin layout in this datasheet for the SST 27SF512 (compatible with 27C256):
http://www.sst.com/downloads/datasheet/S71152.pdf

IC420, IC418, IC417, IC416
Hitachi HD14051B; Single Ended Analog Multiplexer
http://www.datasheets.org.uk/datashe...rticle=1612521

IC412, IC419
HD74HC14; Hex Schmidtt Trigger Inverters
http://www.ortodoxism.ro/datasheets/...or/mXuwtrz.pdf

IC605
Hitachi HD14069UBP; Hex Inverter
http://www.datasheetarchive.com/data...rticle=1612552

IC435
Hitachi HD74HC00P; Logic Gate Quad 2 Input NAND
http://www.datasheetarchive.com/data...rticle=1621483

IC431
Hitachi HD14011B; Quad 2 Input NAND
http://www.datasheetarchive.com/data...rticle=1612400

IC802
Hitachi HD14025BP; Triple 3 Input NOR Gate
http://www.datasheetarchive.com/data...rticle=1612475

IC803, IC603
Matsushita AN6913 Dual Comparator
http://www.ortodoxism.ro/datasheets/...nic/AN6913.pdf

IC407
Hitachi HD74HC139; Dual 2 to 4 Line Decoders
http://www.ortodoxism.ro/datasheets/...or/mXrtqux.pdf

IC101, IC601, IC804
JRC 2904DX; Dual OP-Amp
http://pdf1.alldatasheet.com/datasheet-pdf/view/114306/TI/LM2904DR.html


-Matt

__________________
The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

No, really, stop asking


The Legend Garage

sr5guy

Here is a virgin picture of the above, this is a PY3-A72 ECU, by the way.

__________________
The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

No, really, stop asking


The Legend Garage

Johnny Kim

i dont think the barometric sensor is located within the ecu bc if you look at the case design, its air tight.

__________________

sr5guy

Johnny Kim check out this link:
http://www.arnach.net/service/png/pg0217im.png

It says, in not so many words, that the atmospheric pressure sensor is built onto the ECU board. (which is not airtight, btw... there are plenty of gaps between the connectors and housing). I am ASSUMING that this is the barometric/atmospheric pressure sensor. It also a logical explanation as to why it has a small hole in the side of it to atmosphere.

-Matt

__________________
The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

No, really, stop asking


The Legend Garage

swift

isn't a map sensor techically also a baro sensor so therefore it would be under the hood. Just confused.

I love your plan and i have a friend going into networking that owns a GS so i will let him know whats going on.

latta!

Kenso

The barometric pressure sensor measures the atmospheric pressure rather than manifold pressure/vacuum like the MAP sensor. I'd imagine the sensors work in a similar way though. The atmospheric pressure sensor is there so the ecu can compensate for changes in altitude (and even weather). But for whatever reason, Honda did locate the atmospheric pressure sensor in the ecu. Works just fine there, I suppose it eliminates some wiring that way.

__________________
ITR 00-106
91 6spd coupe
95 FZJ-80

George Carlin on the American Dream (NWS)

sr5guy

Yes a MAP sensor technically can work as a baro sensor. But, it can't be both at the same time! Also, the map sensor is engineered to read inches of vacuum, it probably won't do a good job of reading the subtle changes in millibars of atmosphere. It appears that the baro sensor is very fragile, probably high tech and expensive to make (at the time), so that could be an explanation as to why they mounted it on the ECU board.

If I am remembering correctly, some cars (toyotas?) actually have a solenoid valve that switches the map sensor from intake vacuum to atmosphere.

Does anyone know how the ECU would use the information from the baro sensor?

-Matt

__________________
The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

No, really, stop asking


The Legend Garage

Kenso

To compensate for changes in altitude and weather.

__________________
ITR 00-106
91 6spd coupe
95 FZJ-80

George Carlin on the American Dream (NWS)

Mikey851

Agreed ^. If you drove from sea level to 10,000 ft above, the baro sensor will read this and change fuel and spark based on the amount of atmospheric pressure that is available.

There were some cars which used the MAP sensor to take a baro reading upon key on (This lead to some problems which are explained below). It doesn't matter where it's located as long as it is open to the atmosphere. For instance, when you turn your key on with the engine off, if you measure MAP sensor voltage it will be around the same voltage as you would read with the engine running at WOT.

In fact, if the baro sensor went bad in our ECU, it is probably smart enough to turn to the reading it recieves from the MAP sensor during pre startup self diagnosis when you turn the key on.

The whole reason for a seperate sensor is so that the car can make changes in real time while you drive down the road. There were a few older cars (I believe Chryslers), which used the engine's MAP sensor to diagnose atmospheric conditions. As you would gain altitude the car would start to run like shit. It was a TSB as a customer complaint and the fix was to tell the customer to pull over to the side of the road, turn there car off and then back on; it would then take a new barometric reading and the car would run fine. That is why they started using seperate sensors.

It is located in the ECU for many reasons, such as; there is no need for it to be anywhere else, it saves wiring, it extends the life of the sensor etc. etc.

__________________
http://i26.photobucket.com/albums/c1...Picture076.jpg

Johnny Kim

ohh okay, it was jus a guess and i was wrong lol.

__________________

beav

That is indeed the baro sensor, its the same part used in the civic/teg ecus

KFBhonda

good idea sr5guy.
let me get trained-up at work and school and then i may be of some help, several months down the road...

sr5guy

Thanks man, I'm actually working on it right now. Trying to find a schematic program that can handle a PLCC 84 socket.. otherwise its photoshop....

-Matt

__________________
The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

No, really, stop asking


The Legend Garage