CwazyWabbit Posted June 21, 2011 Share Posted June 21, 2011 I sent mine to Digidash, it came back exactly as I sent it, no damage whatsoever, just increased the total mileage reading to exactly as requested. Is it possible that crcliffords speedo was done before yours Ralph? Maybe they learnt how to use the 3pin port in between doing the two? Or maybe they used his as an experiment to learn how to modify TD5 speedos, all possible I suppose. Quote Link to comment Share on other sites More sharing options...
western Posted June 21, 2011 Share Posted June 21, 2011 Mine was done during November 2007, so it's been in & fully working for a while now. Quote Link to comment Share on other sites More sharing options...
crclifford Posted June 21, 2011 Share Posted June 21, 2011 Is it possible that crcliffords speedo was done before yours Ralph? Maybe they learnt how to use the 3pin port in between doing the two? Or maybe they used his as an experiment to learn how to modify TD5 speedos, all possible I suppose. And mine was done in 2010...so that puts that one out. However mine was to reduce the reading, as i was getting it put back to 0 to go with the recon engine that had just been fitted! whether that makes any difference or not! Chris Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 21, 2011 Share Posted June 21, 2011 And mine was done in 2010...so that puts that one out. However mine was to reduce the reading, as i was getting it put back to 0 to go with the recon engine that had just been fitted! whether that makes any difference or not! Chris That might be the difference, James was kind enough to give me permission to open his speedo up so I'll be having a nose about soon, I'll post pictures when she's been laid bare Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 21, 2011 Share Posted June 21, 2011 Well assuming I have my wiring correct the contents of the memory are as shown in the picture I really should have worked out how to power the speedo up first to read what the actual mileage is! Doh! Anyway it's a fairly small bit of memory I read it out by attaching directly to the chip as that three pin port looks to go to the main processor chip, I haven't traced it yet though. Middle of the 3 pins is just GND. Does anyone know the minimum amount of wires (and which ones) I need to connect to the speedo to get it to come to life? I have James' wiring diagram but unfortunately the pin numbers aren't shown on the speedo so don't know which way to count. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 22, 2011 Share Posted June 22, 2011 cw - how have you read that out then, what hardware/software/protocol/speed? It would be helpful to know the mileage reading of the unit (& any other data it "knows") so we can try to pick the bones out of the data. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 I soldered directly to the legs of the chip using fine wire, theory being I want to make sure it's possible first then we'll work on an easier more accessible method. The chip uses the microwire protocol which is a forerunner to SPI. I used a presto programmer I have from work to do this read but it should be possible to find something cheaper. Once I manage to power the speedo up I'll clock it on a mile or two and see what changes. Also things like resetting the trip counter may help. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 (edited) Warning NAKED Speedometer Pictures!!!!! Once you take it apart you can see the only way to open these is to uncrimp the black metal ring ...carefully. What looks like a seam on the back of the white plastic case is just a flash mark from manufacture. PS sorry about the picture size, I was trying to leave as much detail in the first one to make it useful and then forgot to resize the second, oops... well maybe people like big chips Edited June 22, 2011 by CwazyWabbit Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 Btw I have the datasheet for the eeprom (small chip) but haven't found any details on the main chip yet... I best get on with some work now Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 22, 2011 Share Posted June 22, 2011 How handy: http://www.st.com/internet/mcu/product/64000.jsp Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 1 Million read/write cycles and 40 year data retention..... so not as good as a Series 1 Speedo then Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted June 22, 2011 Share Posted June 22, 2011 Well that answers that question re. read/write cycles Looks good, with regard to powering the speedo up you'd need to supply it 12V on pins 6 and/or 9 of the lower plug. These are the permanent 12V feed, I'm not sure how they are wired internally but supplying on both will cover all eventualities. Pin 10 is the 'ignition on' supply, but the mileage should display without it, ie. in 'ignition off' mode. If you look at the pinout of the plug in the wiring diagram here, you should be able to work out which pins on the speedo you need to provide power to from the plug orientation. Somewhere in the wibbly wobbly speedo thread there is a photo of the speedo back with pin numbers on it, but I'm not sure where! Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 Cheers James I believe this is the post http://forums.lr4x4.com/index.php?showtopic=14892&view=findpost&p=160740 Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 Current mileage is 22953.0 which is not obvious in the hex dump, will clock it on a bit and see what changes when I'm on my lunch break. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 Looks like it counts down from FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF James your Speedo now reads 1.0 Total It's not a simple countdown, so I need to work out how to calculate an exact figure... but for now enjoy Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 (edited) I should add it's the first 8 bytes 16 bit words of the flash recording the mileage, the fractions of a mile aren't stored and neither is the trip mileage from what I can see. Edited June 22, 2011 by CwazyWabbit Quote Link to comment Share on other sites More sharing options...
crclifford Posted June 22, 2011 Share Posted June 22, 2011 Warning NAKED Speedometer Pictures!!!!! Once you take it apart you can see the only way to open these is to uncrimp the black metal ring ...carefully. What looks like a seam on the back of the white plastic case is just a flash mark from manufacture. Glad i was of some help... I'm good at the taking apart...not so good at the elctronics side of things! Hopefully, this means that future converters won't have to fork out over £100 to get theirs changed!! Chris Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 22, 2011 Share Posted June 22, 2011 Reason for counting down from F is that flash RAM erases to all 1's, and then you can write (blow) bits back to zero. I suspect they're blowing individual bits to avoid too many erase-write cycles (in fact they may never erase it after it leaves the factory) just realised that's a daft statement, although I suspect there's some cunning reason for it what with the thing having to store important info without being upset by a power-cycle or whatnot. Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted June 22, 2011 Share Posted June 22, 2011 Good stuff! I know the trip mileage is lost if you remove the permanent 12V supply, so it would make sense that this isn't on the 'permanent' EEPROM. I'm sure the total mileage features decimal points though, and is 'remembered'. Unless that part (the decimal) is stored on volatile memory like the trip mileage and removing the 12V permanent supply would revert your odometer to the whole mile. I know that when you cross 100k the decimal point disappears and you only get whole miles. PS. It was 197,672 miles that that particular speedo wants to end up as Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 I think you have hit the Nail on the head there Sir! (Mr Freezer) It also explains something that was puzzling me, when you add a mile on it takes 1 away from one of the 16bit words, when you add the next mile on though it takes 1 away from the next 16bit word. I imagine this is a crude form of wear levelling for counters and would make the flash last longer. Thanks for that Now will just need a few more experiments to work it out properly..... then I think we should look at that 3 pin port ...... from what Ralph and Chris have seen from digidash it would seem you only have to open the instrument to remove miles so I'd guess adding miles on can be performed externally via the 3 pin port. Unless Digidash just used a drill on Ralphs! Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 Good stuff! I know the trip mileage is lost if you remove the permanent 12V supply, so it would make sense that this isn't on the 'permanent' EEPROM. I'm sure the total mileage features decimal points though, and is 'remembered'. Unless that part (the decimal) is stored on volatile memory like the trip mileage and removing the 12V permanent supply would revert your odometer to the whole mile. I know that when you cross 100k the decimal point disappears and you only get whole miles. PS. It was 197,672 miles that that particular speedo wants to end up as The fractional miles are lost when the permanent 12v is disconnected. Apparently the fractional mileage is only shown while the total is less than 100 000 as ther isn't enough space afterwards. Quote Link to comment Share on other sites More sharing options...
MrKev Posted June 22, 2011 Share Posted June 22, 2011 (edited) I think I may have worked it out. To program James' Milage in, I reckon you need to program CFBD into the first 8 words of the EEPROM, i.e. instead of the FA64/FA65 that's there at the moment. If I'm right, I'll tell you how I did it Kev p.s. I might be approx 10 miles out, so make the first 16 words look like this: CFBD CFBD CFBD CFBD CFBC CFBC CFBC CFBC Edited June 22, 2011 by MrKev Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 I think I may have worked it out. To program James' Milage in, I reckon you need to program CFBD into the first 8 words of the EEPROM, i.e. instead of the FA64/FA65 that's there at the moment. If I'm right, I'll tell you how I did it Kev p.s. I might be approx 10 miles out, so make the first 16 words look like this: CFBD CFBD CFBD CFBD CFBC CFBC CFBC CFBC Tsk, You are under by 3 Miles Well done! Spill the beans then Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 oops I can't count, under by 13miles sorry Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted June 22, 2011 Share Posted June 22, 2011 Strange CFBC CFBC CFBC CFBD CFBD CFBD CFBD CFBD = 197671 CFBC CFBC CFBC CFBC CFBD CFBD CFBD CFBD = 197673 I can't get it to 197672 .... I drove around for a while at 120mph till it displayed 197672 but when I disconnected all power it returned as 197673, tried it twice now. Quote Link to comment Share on other sites More sharing options...
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