I just finished the MegaJolt/EDIS install on my old 911 and it worked from the start controlling the ignition. I struggled to connect to it however and only managed to get intermittent contact with the laptop and serial adapter. Today I finally managed to find an obsolete laptop with serial port on it and have spent most of the day tweaking the ignition map. I couldn't be more pleased with the user friendly interface, and my engine is purring.
This problem with serial adapters is unacceptable however. It is next to impossible to find PCs with serial ports in this part of the world, and when the Megajolt works so poorly or not at all with serial adapter this is a serious problem.
I have been using both Megasquirt EFI and the old GPS with serial adapters and NEVER ever had an issue, so blaming on the serial adapters just doesn't fly. You really need too fix the problem
MegaJolt and serial adapters design problem - what is this ?
Moderators: JeffC, rdoherty, stieg, brentp
Whilst it is possible that Megasquirt might be more tolerant of bad USB-serial adaptors the fault is very clearly with the adaptors. Of the bad USB adaptors that I have seen the ones that are on the borderline of being OK seem alright at low speeds (such as the 9600bps rate that Megasquirt V1 uses) but get very flakey as the symbol rate increases beyond 19200. MS2 uses 115200bps so I would expect that many Megasquirt users running with an MS1 processor would find problems with their adaptors if they swap to MS2. In fact of the USB adaptors that we tested here looking for ones that we were happy to sell we found no less than 3 different models which worked fine with MS2 at 115200 until you tried to do firmware downloads - at that point you had a 50-50 chance they would corrupt the firmware. Needless to say we don't sell those ones!
The only way you could "fix" the megajolt to work with a few more of USB adaptors would be to cripple it by running at 9600bps. Even if you did that wouldn't you be worrying all the time whether the map file you just downloaded got corrupted on the way by the USB adaptor? Personally I prefer the current setup - either you've got a good adaptor and it works perfectly in all situations or it doesn't work at all.
The only way you could "fix" the megajolt to work with a few more of USB adaptors would be to cripple it by running at 9600bps. Even if you did that wouldn't you be worrying all the time whether the map file you just downloaded got corrupted on the way by the USB adaptor? Personally I prefer the current setup - either you've got a good adaptor and it works perfectly in all situations or it doesn't work at all.
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Complete Megajolt packages, EDIS kits, Trigger wheels and everything else you need for your megajolt install
www.trigger-wheels.com
Thank you, cng1 for the insights. For reference, the V4 version of Megajolt communicates at 38,400 BPS.
On the USB-Serial front, the variants of USB-Serial adapters is mind boggling- and they are all implemented with varying levels of quality:
-board design
-RF shielding
-correctly implementing the circuit per the USB chipset manufacturer; even controllers based on the popular Prolific chipset could have problems...
The best thing is that our future projects will have native USB support, neatly side-stepping the issues around the USB-Serial adapters. It will likely be a source of a few new problems, but I would certainly trade those as we'll at least have a chance to address them!
On the USB-Serial front, the variants of USB-Serial adapters is mind boggling- and they are all implemented with varying levels of quality:
-board design
-RF shielding
-correctly implementing the circuit per the USB chipset manufacturer; even controllers based on the popular Prolific chipset could have problems...
The best thing is that our future projects will have native USB support, neatly side-stepping the issues around the USB-Serial adapters. It will likely be a source of a few new problems, but I would certainly trade those as we'll at least have a chance to address them!