Instructions to change fuel maps on 14CUX Griffith, Chimaera

OK, this bit I understand; sounds very elegant.

I don't quite see the analogy between the small model data, code and stack segment pointers all being the same and addressing that is partially implied ... but this is getting very geeky and I don't want to distract you from V.3, so I'll figure it out latter.

Colin

Please can you consider adding status indicators to RoverGauge for the following:-
Inertia switch
Heated screen
Auto/neutral/manual
Air/Con

Thanks for all the previous updates.
Steve

Motorola did supply public example code but it tended to be fairly generic. We occasionally would do customer specific stuff but it was rare. In some cases, the circuit board developers would also write the code but in others it would be software developers. There is/was no fast rule on this. One of the major problems for any development is when the hardware is changed without realising the effect on the software and vice versa.

The main activities with Lucas was working out how to debug and test the code without destroying an engine. You can't simply stop the processor in mid execution to look at variables as it would cause havoc with the engine. It could leave injectors on full time and potentially hydraulic the engine. Same dangers happened when the code crashed or had a bug in it. So you had to stop the engine first and then the processor. By which time, the context is lost. The solution was to force all activities externally so that they could be captured with analysers etc. The serial port was a help but you could never be sure exactly when the data was read or even if the memory block was read in the same time frame.

Also bear in mind that this development started in the mid 1980s when micros in embedded designs like this was in its infancy. There were none of the tools available that there are today such as JTAG, symbolic debugging and so on. The 14CUx was probably the first digital ECU as well so it was very much state of the art and right on the (b)leading edge of technology.

I was also involved in training and writing for Motorola as well as my normal day job hence DaveP's comment about TA (technical Author). It was something that I did in my spare time as Motorola had a very lucrative bonus scheme for external publications... The University where I'm lecturing specified a couple of my books and then discovered I lived locally. The rest is history as they say.

I can definitely look into adding the inertia switch, screen heater, and A/C status. The gearbox selection is already displayed in RoverGauge next to the "Selected gear" label -- although if this isn't working correctly, please let me know. It's one of those features on which we didn't put much emphasis, and therefore didn't get a lot of testing.

I'll post here when I have a new version ready.

Dave, as a fellow nerd you are not supposed to know this much about literature!

I wanted to mention earlier during discussions about the road speed that the flowchart on the G-drive has several graphs that may interest you, Steve and maybe others. The last page shows three graphs. Data was captured at 1 second intervals during an actual road test.

The top graph shows the timer overflow counter. The MPU sets a bit when the free running counter overflows and software checks this often enough to update it's own counter. This is what periodically latches the VSS state change counter into the road speed variable.

The middle graph shows the number of VSS high-to-low state changes since the last time the road speed was updated. This is a representation of VSS square wave frequency.

Finally, the third graph shows the 14CUX road speed. You may notice that this is an outline or envelope of the middle graph. This makes sense since the overflow counter and state change counter are cleared together. In fact, Lucas made sure that they were cleared together by wrapping the clearing operations with an interrupt mask.

Colin, thanks very much for adding the screen heater and A/C inputs. I’ve been looking at the code too long and forgot the gear selection is already in RG and yes it works correctly. I only mentioned the inertia switch input as I spotted it in the adc vector table and it was once questioned when FFMan couldn’t get his bench 14CUX running. It’s never an issue in the UK as our inertia switches are only connected to the fuel pump 12v supply and not directly to the ECU.

Mark
Here's the AFR for map 2 at a steady 60 mph and hopefully answers your question. It's great to see the AFR merged with RG without a time delay. The RoverGauge speedo it a bit random and usually over reads at low speed and then under reads at high speed.

#time         MPH    RPM    throttle   mafPercent   MapRow  MapCol  pulseMs   AFR
18:47:54.324   27   2274    0.198436    0.103297       1      9     3.18      14.5
18:47:54.829   27   2270    0.220919    0.132736       1      9     3.395     15.3
18:47:55.373   22   2267    0.231672    0.147253       1      9     3.617     15.5
18:47:55.988   22   2269    0.232649    0.1476         1      9     3.627     15.6
18:47:56.532   22   2275    0.232649    0.147947       1      9     3.631     15.6
18:47:57.012   22   2280    0.232649    0.1476         1      9     3.611     15.7
18:47:57.540   22   2288    0.232649    0.144939       1      9     3.623     15.7
18:47:58.100   24   2293    0.233627    0.145633       1      9     3.646     15.7
18:47:58.596   24   2299    0.236559    0.153094       1      9     3.668     15.7
18:47:59.107   24   2301    0.236559    0.152632       1      9     3.687     15.7
18:47:59.652   25   2308    0.236559    0.151938       1      9     3.666     15.6
18:48:00.186   25   2314    0.236559    0.149451       1      9     3.676     15.6
18:48:00.820   22   2324    0.236559    0.148409       1      9     3.626     15.5
18:48:01.370   22   2299    0.0537634   0.044013       0      9     1.894     14.2
18:48:01.876   25   2267    0.0537634   0.041642       0      9     1.956     13.5

There's an inertia sensing input from a relay on my car that sits betwixt the inertia switch and the ECU:

Relay R8 – Fuel Pump Control

Pin out Connections (refer to Bible Circuit Diagram and Fuse panel block annotations). Cable colours in brackets.

Relay Pin 39
+12 V circuit to energise coil with ignition switched On:
Ignition switch – Block D 58ar (WR) – Block C 56ak (W) – Block H 50w – relay 39

Relay Pin 37
Ground circuit for coil:
CDL3 and RISTS12 (BW) – Block F 50z (BW) – relay 37

Relay Pin 38
+12 V feed control from ECU to relay contact:
ECU – Block J 58 (Y) – Fuse 14 - Block I 58D (Y) – Block E RS (Y) – relay 38

Relay Pin 36
With relay energised and contact made supply +12 V to Inertia Switch, and if closed circuit to Fuel Pump:
Fuel pump – Inertia switch (Y) - Block F RL (YB) – relay 36

Relay Pin 59
Not used.


The R8 relay is in addition to the fuel pump relay in the floating loom. Have you got this relay on your precat Steve?

Mark, Ah of cause, the Tornado chip is on a scrambler so we can't alter the fuel tables. Shame, as MA has done a lot of R&D over the years and come up with some good ideas, like reduce cranking and warn up fuelling etc.
Sounds like its time I use Dan's rebuild project to merge the Griff 400 precat map 2 into the Chimaera 400 cat prom and then you'll have the best of both plus with the later TVR code. Once tested we can then look at extending the RPM points, it's good to start with the standard maps. I hope it's not urgent as I'm currently working on my car in the evenings this week, but I'm sure I'll make time as I love this stuff but I don't know why.

Just trying to get the same data- first problem- the time logger program only seems to allow for Com 1 and 2, although my serial USB port is com 3, it wont allow a manual input, and I assume you have done a lot of editing from the log files and merged it with the time logger file? Whats involved?