Couldnt really find a section for this..

[Streetholden]

I was looking at that sorta thing, but the sender apparently requires a 12volt feed then sends a signal in a wave length form and thats way out of my league of knowledge.

[jxx]

More 80c51 code
green pcb lcd unit

compared raw bins and it's different code

hrm, upon further investigation of the cluster i think this is actually early vn it's got a vr front on it but everything else looks early pins in the speedo and tacho faces and the vdo sticker on the lcd unit is date stamped 14589 which had fallen of and was inside the cluster.

so still searching for newer clusters to dismantle......

[festy]

I've got most of the interesting functions worked out from the first bin, so recognised a few of them in this one straight away.
There's a bunch of new routines here, and I think it handles the external interrupts a bit differently - how different are the PCBs?
There's an extra routine writing to the nvram - does the VR have any additional cluster functions compared to the VP?

[jxx]

No different functions.

Quite alot of difference in the board designs where the warning lamp/buzzer connection are to the left of the mcu, couple of extra diodes, transistors different.
nec upa chip has gone and a lm2902 has possibly taken it's place but can't tell by looking will need to research the chips and draw up a schematic.
thought there was a difference in the clock crystal but it's changed what it looks like, the big blue component on the green board near pin 20 is marked X10? just had to bend it out of the way to read, thought it was a cap.
has an X2444PI chip instead of the CAT24C44

Put the Green mcu in the blue board and it functions
fails diag even with the right nvram code.
and the buzzer i have put on the vn board let out a loud high pitched noise when ign power was applied and i think i'm now half deaf.....

the diag mode fail is quite interesting with the green mcu in the blue board when changing modes, the lcd screen test is totally different, instead of selecting all segments it's doing it in a pattern and order selecting different segments, will try and get a video of this.

blue mcu and nvram into the green board works perfectly, diag mode works with no fail message.

nvram

Code: Select all

01A1 6926 FFFF E758 CC33 5BA4 619E 56A9
CC33 5BA4 619E 56A9 CC33 5BA4 619E 56A9

[jxx]

Green mcu & nvram in Vn blue board, diag mode testing lcd screen segments.

in advance i apologize for the poor pixelated quality, phones don't work well up close and by the time i compressed it.... you'll get the picture though of it's odd behavior.

[88GreenVN]

http://www.level3patchlooms.com/Trip_Computers.asp

A link to how to ID your trip computer. (I tried to past the table into the post but it was just all over the palce)

I had forgotten that there was a minor change from VN to VQ on the main chip - so 3 main chip numbers to play with

[88GreenVN]

I've got most of the interesting functions worked out from the first bin, so recognised a few of them in this one straight away.
There's a bunch of new routines here, and I think it handles the external interrupts a bit differently - how different are the PCBs?
There's an extra routine writing to the nvram - does the VR have any additional cluster functions compared to the VP?

In the years I've been playing with trip computers I've not seen an extra user function between the VP and VR.

[jxx]

the numbers in your chart, are they the numbers on the screen print of the pcb?

I have a blue pcb 40737 which is late vn, the original owner changed the cluster with one from a wrecker that was marked VN, VDO date sticker is F120391

[vs ss]

Hi yes from memory when you put a vr-vs into a vn-vp it sends one of the diodes up in smoke.
I think it is one near the main plug for the trip computer, prob a bit of usless info but worth a mention.
And there are no extra functions between the two.

[jxx]

VR/VS Green PCB 43365 vdo sticker E17196
Board looks identical to the blue and red pcbs

Tested mcu and nvram in a blue pcb, works 100% bench test, 91 (blue/red) nvram matches the 96 code in the important bytes so is compatible.
Festy is the built in uart initialized in the code? (i did have a quick look but didn't see the port speed) if so then it shouldn't be to hard to rewrite vp trip comps to run in vr/vs and vise versa without removing the mcu.

i think this completes the collection and 3 revisions of code

Now a bit off topic, it wouldn't be hard to add 3 x 7 segment led/lcd displays with driver ic's to the existing board but how hard would it be to rewrite the code and have a permanent digital speedo in the cluster? (or as there are quite a few unused output pins on the current lcd driver chips is this feature already coded and just not connected?)
and some pinouts i have seen a tacho input on the trip comp inputs, how can we unlock and display that?

nvram dump

Code: Select all

  00   01   02   03   04   05   06   07
+----+----+----+----+----+----+----+----+
 01A1 6926 FF00 DF20 55AA 1BE4 7D82 BD42
 55AA 1BE4 7D82 BD42 55AA 1BE4 7D82 BD42