Third Gen Black Faced Meter (BFM) Information - 2015-01-09

[rkrenicki]

Assuming everything will reach the way it is... I guess it depends on how motivated I am this weekend to do it. It will be nice to have two trip meters again too, which I found that I actually used often enough to miss it when it was gone.

[rkrenicki]

Looking at my order status on Mouser shows that they now have in stock all of the harness side connectors for these cars. The 30, 18, 16, and 14 pin "Socket Housings" as well as the Socket Contacts.

All of the cluster side connectors are still on backorder, but it looks like their shipment dates got bumped up a few weeks to Jan 1.

[rkrenicki]

As part of the "BFM try 2", I am going to try to reverse engineer these kph/mph adapters.

I have another one in hand, and it is extremely simple.. just one PIC microcontroller, two transistors, a capacitor, and five resistors. Absolutely not worth $50+, as it is only about $4-5 in parts. The hard part is going to be extracting the software off of the controller, but knowing what kind it is and how it is wired up would tell me alot to write my own firmware if necessary.

[amgarrety]

As part of the "BFM try 2", I am going to try to reverse engineer these kph/mph adapters.

I have another one in hand, and it is extremely simple.. just one PIC microcontroller, two transistors, a capacitor, and five resistors. Absolutely not worth $50+, as it is only about $4-5 in parts. The hard part is going to be extracting the software off of the controller, but knowing what kind it is and how it is wired up would tell me alot to write my own firmware if necessary.

I had a really strong feeling it wasn't $50, after seeing that small microcontroller through the heat shrink. I don't have the means to write that code though, nor extract it.

[rkrenicki]

Luckily the programmer that I use for EEPROMs, can also do PICs and some Atmel chips. So, trying to read it isnt that hard, assuming that they did not protect the chip from being read back. I will give it a try over the weekend.

[rkrenicki]

My 090 showed up today, and I noticed that the lights for the Cruise Set, and for FWD were absent.. I am not sure if that is by design, or the prior user removed them.. Luckily, I have a few bulb holders left over from the 030, so I populated them for now.

Next up, testing it out and verifying the pinout that I have.

[rkrenicki]

After those locations were populated, they do indeed work. So does AT Oil Temp, which was missing from my 090 pinout.. it is on B4.

This cluster has been around.. it has over 191,000 kms on it.

[amgarrety]

I don't even have a cruise set light. It's very possible the car you got it from didn't have cruise. As I understand, it wasn't a very common feature in Japan.

[rkrenicki]

Well, I am just happy that it will actually say "cruise" after this is done.. as "power".. while it gets the idea across.. is not the best replacement.

[rkrenicki]

removed.. for now.

[amgarrety]

Are you going to try to replicate them?

[rkrenicki]

That's the idea. There really is no reason for it to be $50, and that's even on the cheap side! Some places charge more like $80-100 for these things.

[amgarrety]

Yeah I know, I jumped on this at the price I found it at, and that's sad.

Just being a business student, I must say this, but make sure you don't get in trouble for copying their code or anything. I don't know what restrictions they have on their products (if any), but stay on the safe side haha

[rkrenicki]

Well, I can write my own code for this. What I am taking from this schematic is that the VSS signal is a series of ground pulses. If I slow down that pulse rate to a ratio of 1:0.621, thats all it needs to do. The more I am looking at this, the less I am convinced that I need to get the code on this chip out.

[amgarrety]

Couldn't you just use resistors?

[rkrenicki]

No, its the pulse rate that needs to change, not the voltage. Basically, for every 50 pulses that comes in, it needs to spit out 31.

Since the pulse rate is fairly high (4104 pulses per mile from what I see on the internets), dropping pulses will only implement negligible needle lag.

I also found a schematic and source code for another mph/kmh adapter, however it is significantly larger and more complex than this design. It implements dip switches for adjustments and test signals. I am sure I can strip down this code to just what is needed instead.

http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=15639

[rkrenicki]

I received the 2723 bulbs today, and finished replacing all of the bulbs in the 090. I took it apart to cover the k in km/h, and to dump the EEPROM for when I need to reprogram it.

Unfortunately, the 090 does not use the same type of EEPROM chip that the 84A, 020, or 030 uses. It uses a SOIC-8 "L56R" instead of a DIP-8 "93C56" chip, the only difference is that it is a surface mount part instead of a through hole part. This is not a big problem as my programer will write these too, however I do not want to pull the chip off now to put it back on, and then take it off when I go to actually program it.

But, I am happy to have a functioning Cruise Light

[amgarrety]

... however I do not want to pull the chip off now to put it back on, and then take it off when I go to actually program it.

Couldn't you place a chip socket on the board? That way you can remove and replace it as much as you want without destroying the contacts. I thought about doing that with my cluster, but I figured I probably wouldn't remove the chip again.

[rkrenicki]

I did on the 030, but those sockets are dirt cheap (about 15 cents or so), but SMD sockets are not cheap or even small.. It may not even fit within the cluster anymore.

It's fine, I will just wait to dump it for when I actually go to reprogram it and do the removal once.

EDIT: Actually, this is an SPI based flash chip.. I might be able to do this with my BusPirate adapter instead without even removing the chip from the cluster.. hmm... some internet browsing is needed for this I think.

[rkrenicki]

Christmas came a little early!

[amgarrety]

Nice! I'm guessing you've already started?

[rkrenicki]

No, not yet.. I have something very different planned for these.. but the rest of the parts are not here yet. in fact one of them I need to order which I am going to do very shortly.

But, when I am done, I hope to have a very polished end product, which Yamazaki should be able to benefit from.

[Yamazaki]

Yay!

[rkrenicki]

A little sneak peak at what I just ordered for this project... This is a small portion of the CAD drawings..



I just need to order a few additional parts, and I should have enough parts to make two complete sets of adapters.

[rkrenicki]

My circuit boards finally showed up! This is my final design for a USDM to JDM BFM adapter.

I created a layout for the JAE connectors for FreePCB, and laid out what wires go where. in order to connect to the wires needed for the female connectors, I decided to use DA-15s and DB-25 connectors as they are cheap and plentiful. This also allows the adapter to be reconfigured for any BFM, however the PCB is specific to the H6 version of the USDM car.

I use oshpark.com (Formerly DorkbotPDX PCB service by Laen) for my circuit board fabrication, they do fantastic work and they use this cool purple color for the solder mask. All of his boards are in multiples of three so I now have enough to make an adapter for myself as well as for YamazakiSubaru.

The connectors were ordered from Mouser further up this thread.

But, enough of the talkie-talk.. heres the pictures!

Empty PCB, Top:


Empty PCB, Bottom:


Populated with the USDM-side JAE connectors


End shot of the JAE connectors:


Fully assembled, includes DB and DA connectors, and a SVASpeedos.co.uk adapter mounted on the board.

[rkrenicki]

I still need to finish the wire side from the D-subs to the BFM, but I should be able to get that done tomorrow.

[amgarrety]

Wow that's awesome, I'm really jealous of how neat that is going to look.

[Yamazaki]

That IS awesome! Does that incorporate a kph->mph resistor? Will it fit behind the cluster (it isn't too big)? Oh, I am SOOO excited!

[amgarrety]

That IS awesome! Does that incorporate a kph->mph resistor? Will it fit behind the cluster (it isn't too big)? Oh, I am SOOO excited!

I was wondering that too (about the size of the board).

Yamazaki, that little piece of green circuit board (with RBGY printed below) in between the connectors is the speedo resistor. I think that is really cool that it is all just built in. That really cleans things up. You might have a easily sell-able product here if enough people get their hands on BFMs.

[rkrenicki]

To be honest, it will be a little tight up in the dash.. but I will find a way to make it work. Being that there is room to stash the CCFL inverter up above the ductwork, and this board is shallower than that, it should be okay.

In hindsight, I should have shortened up the board a bit, but that would have made my trace routing a little more complicated.