Serial protocol

[grom_e30]

iv been playing with an arduino, grabbing info to display on a small screen from serial, and on ms2 v 3.3.2 it works pretty well, but when i try it on ms3 pre 1.3alpha9 it does not work so well, iv changed the data table length to match the f/w also increased the serial buffer to, i can get some info from it like rpm and afr1, also sometimes i get extra or duplicated bytes meaning i receive more than im expecting, is the serial protocol different between ms2 & ms3?

[racingmini_mtl]

The protocol is the same. The information specific to the command and data is in the ini file for the firmware you're using. If you're not getting the correct data, you likely have either a serial comm issue or an arduino issue.

Jean

[jsmcortina]

iv been playing with an arduino, grabbing info to display on a small screen from serial, and on ms2 v 3.3.2 it works pretty well, but when i try it on ms3 pre 1.3alpha9 it does not work so well, iv changed the data table length to match the f/w also increased the serial buffer to, i can get some info from it like rpm and afr1, also sometimes i get extra or duplicated bytes meaning i receive more than im expecting, is the serial protocol different between ms2 & ms3?

Is your CRC checking detecting these problems?

James

[grom_e30]

I'm not totally sure if I'm using the CRC. But on ms2 set the table length as the och block size can read temp, AFR, battery and rpm. Chang block size as on ms3, can get AFR and rpm, but not temp or tps. When you mention the CRC is that aimed towards tuner studio using it or arduino? Looks like if got some homework to do tonight and read up on this lot some more

[racingmini_mtl]

Have you checked this: http://www.msextra.com/doc/ms3/files/ms ... l_0.05.pdf ?

Jean

[grom_e30]

I have tried to look at that before but the file is not working.

[racingmini_mtl]

Click on the confirm line in the window you get with the link.

[grom_e30]

So would the CRC still be there with the A command?

[jsmcortina]

I'm not totally sure if I'm using the CRC. But on ms2 set the table length as the och block size can read temp, AFR, battery and rpm. Chang block size as on ms3, can get AFR and rpm, but not temp or tps. When you mention the CRC is that aimed towards tuner studio using it or arduino? Looks like if got some homework to do tonight and read up on this lot some more

The CRC is the biggest single change in the protocol, you are supposed to use it to validate that the data you received is valid.

James

[grom_e30]

I'm trying to wrap my head round this so to request the information from the ecu with the "A" command it should be 7 bytes long 0x00 0x01 0x41 0xd3 0xd9 0x9e 0x8b. Data length then the command followed by the crc

[racingmini_mtl]

The 'A' command will work without the wrapper and will then return an unwrapped response. But you won't know if there was any communication error. And if you do wrap it, then you're correct about the resulting command.

Jean

[grom_e30]

OK is it always an unwrapped response from the A or if you wrap the command you get a wrapped response?

[racingmini_mtl]

If you send a wrapped command, you receive a wrapped response.

Jean