- VEMS
VEMS is a low volume commercial engine management system. VEMS is unlike most other EMS's in that it used to be public domain and then a form of open source.
History
The original version of VEMS was called MegaSquirtAVR and was a re-write of the popular but inadequate (at the time) MegaSquirt system. At some point it was suspected that some of the VEMS design had been stolen by a popular automotive electronics company and the design was closed from that point on.
Hardware
VEMS can be purchased as a pre-made board or a complete system with several options in between. Most of the design is built with SMD components to keep size down and reliability up.
Microcontroller
VEMS uses the AVR Atmega128 which is significantly more powerful than the original MS1 CPU.
Revisions
The early MS based version was called 2.0 however that has been out of circulation for some time. The 3.0 board was the first "GenBoard" variant. Development was closed at 3.2 and the current version is 3.4. All 3.X versions incorporate one or more wide band controller.
Firmware
VEMS firmware is primarily written in the C programming language, however some parts are distributed in binary and not C for IP protection reasons with an NDA.
Documentation
The VEMS project is poorly documented compared with the MegaSquirt system which many believe is over documented. This has caused adoption of the system to be limited and slow.
Tuning Software
Tuning is done with MegaTune as written by Eric Fahlgren for the MegaSquirt system. MegaTune is licensed under GPL and can therefore be used by anyone.
Licenses
The original MSAVR system is public domain and still available for download. This original source is obviously MegaSquirt based and therefore surrounded by some controversy. Later source was under an open source license, however since 3.2 the system is effectively closed source.
Comparison
"DIY" fuel injection systems
Note: Both MS1 and MS2 are effectively just processors, both of them require a main board to function. The three different available main boards, 2.2, 3.0 and 3.57, are cheap, reasonable, and expensive respectively. Consequently, MS1 or MS2 being cheap relies on the use of a 2.2 or 3.0 board both of which have some issues.
External links
* [http://www.caffrey.dk/megasquirt/index.php - original MSAVR site]
* [http://www.vems.co.uk/ - UK distribution and english support forum]
* [http://www.vems.hu/ - Main VEMS site]
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