dnb

I'm told that the baud rate of the ECU select monitor connector is very non standard. (1953 bps or something similar).

Can anyone confirm/deny this, as I want to use my laptop to view the ECU data and it only has a standard serial port.

Any ideas for simple baud rate converters - would prefer not to go to a PIC solution. I would like to have a laptop connector for data logging...

(I have seen a couple of web references and the ECU monitor thread)

dnb

Just found out that my Psion 5 can recieive with a baud rate of 2000 bps. Maybe this will be close enough to the ECU.

Have to code an OPL hex reader now

All ideas / comments welcome!

Stephen Cole

Depends what MY you have

The early ones uses a wierd rate and plug
http://www.keisei.tsukuba.ac.jp/~kashima/gc8-e.html

The later ones MY99 ? onwards
use a standard OBDII connector and rate
(can't remember the details, but Stephen Done is the expert)
http://www.ecutek.com/
http://www.steve.ukmail.org/car/

David_Wallis

Dnb,

What year is your car??

David

dnb

Let's take this bttt...

It's a UK 96. Think the baud rate should be approx 2000 bps (19xx, more likely). Unfortunately I don't yet have anything to rx at that rate.

Thanks everyone!

Chris.Palmer

In which case may I wish you all the best. Owners of the older models desperately need a decent ECU reader.

Please keep us all posted with your progress.

Cheers m8.

PS - as mentioned above (& if you haven't already) - check out this web site - loads of very useful info on earlier ECUs http://lillith.sk.tsukuba.ac.jp/~kas...r/index-e.html


[Edited by Chris.Palmer - 28/05/2002 09:12:01]

David_Wallis

Let me know how you get on, or if I can do anything to help... what we could do with is a decent translation of the above site.

David

AndrewC

The bitrate for communition via the select monitor port is 1953bps or 4Mhz/2048, deviation from this rate will lead to data loss.

It is not as simple as saying pre-MY99 use a propriatory protocol and MY99 on use OBD2, AFAIK all MYs can comminucate using the propriatory protocol (which is a lot faster than OBD) although the addresses to read are different from MY to MY. For instance my MY98 can has both the dash mounted OBD connector and the older style Subaru connector and can have both types of select monitor connected?

From what I know (not a lot), whilst the information on the above site is correct wrt the communication protocol, the memory addresses are only correct for the STI V2.

I have a simple AVR circuit and code which allows me to read portions of memory and write them out on RS232 but I am awaiting our friend in Estonia to release details of the important addresses for the MY97/98 ECU.

dnb

Thanks for the bit rate. Am thinking of making a pic or cpld based thing to read the awkward baud rate and output it at something more sensible (rs232c @ 9600 bps probably)...

However, if there is something i can easily buy to do the job (ie cheap!!) then that would be better. I'm not bothered about soldering etc...

Once data can be collected on a computer, there is a chance of getting things cracked.

AndrewC

That's pretty much what I am doing, I use a 4Mhz AVR90S2313 with the hardware UART connected to a MAX232 at 9600 and a software UART (programmed using Bascom-AVR) to talk to the ECU at 1953.125bps.

Unfortunately at the moment I haven't got the time to spend hours debugging the ECU code so I am relying on Illimar to deliver the necessary info.

Andrew...

Stephen Cole

Andrew

Please keep us all updated on how you get on

We older MY owners need something we can use

Stephen
MY94 WRX 5-door

Chris.Palmer

Andrew,

Illimar?

ps isn't the My97-My98 ECU different to the pre My97?

pps cheap excuse to btt again coz its important



[Edited by Chris.Palmer - 5/28/2002 9:01:54 PM]

dnb

Andrew,
Father in law has just asked me to help him implement a control system for some yacht equipment (microcontroller based & a long story...)

Have suggested to him that Atmel's offerings could be suitable, and he has agreed, so I should soon have the hardware.

Can I steal your UART code to test my ECU when I get my programmer system up and running? It will save me time, as I will be implementing F.I.L's control system in the evenings as well...
(Probably won't have full Bascom-AVR at the start...)

Thanks.

Chris.Palmer

Posted question in General for Japanese Translation

Chris.Palmer

Babel Fish http://babelfish.altavista.com seems to provide a simple but literal translation from Japanese to English of http://www.keisei.tsukuba.ac.jp/~kashima/gc8-e.html


Will have a closer look tomorrow & see if it helps

Regards,

Chris


[Edited by Chris.Palmer - 5/29/2002 9:33:33 PM]

dnb

Had a look at the japanese translation...

ASCII mode is very useful, and a baud rate of 4800 (approx) is OK for direct connection to a standard laptop. Just need to know how to put the car in ASCII mode...

David_Wallis

that link doesnt work for me... everybody seems to be able to find more info on this site than me.

David

Chris.Palmer

For some unknown reason this direct link http://www.keisei.tsukuba.ac.jp/~kashima/gc8-e.html doesn't appear to work,however, if you use Babel fish to go to http://lillith.sk.tsukuba.ac.jp/~kas...r/index-e.html

Then click on the "Subaru ECU" you can get to the page.

Cheers m8

dnb

Don't want this to disappear that fast. Has anyone made any sense of the Japanese translation - especially the ASCII mode talked about?

Chris.Palmer

I'll email the site owner & politely request assistance.

James_PowerMad

There is really quite a bit of margin if you want to communicate with the ECU at 2000 bps.

You send asynchronous serial data, with 1 start bit, 8 data bits, and 1 stop bit. Each of these bits last 51.2 ms (for 1953 bps), or 50 ms (for 2000 bps).

A serial port receiver should work by looking out for the leading edge of a start bit, and then waiting 1.5 bit lengths and sampling the first data bit (bang in the middle of where it expects the bit to be), then delaying by 1 bit length and sampling the second bit.......

If by the time of the stop bit, the sample point is still comfortably inside of the transmitted bit, then the data will be received OK.

With our two bitrates, the error per bit length is 1.2 ms, which we multiply by 9.5 = 11.4 ms, which is comfortably less than 25 ms, which is the amount that we would have to stray by to loose sync with the transmitter.

Providing each byte of data is sent with a few tens of miliseconds apart, then the receiver should get the data.

David_Wallis

bttt

Chris.Palmer

Ditto

Chris.Palmer

Just to let you know (& to boing) I've Emailed a few peeps about the site hoping to get more info on ASCII mode.

Will keep ya posted