A version that allows multiple 'message blocks' to be read:

Here allowing MIDs of 128 and 144.

Yes, and no.

It actually stores a 16bit sum - the twos complement of this (% 256) needs to be 0.

Martin

The reset needs the checksum resetting too. So will only receive one message as is...

V2. 0 this evening

Regarding the row of two byte PIDs, for example: engine speed - PID 190, data 087 009 - PID_data[0] /; 087;/ + (PID_data[1] /;009;/<<8) I get a 16-bit value and multiply it by 0.25 (res/bit) So - the PID - get from PID[0] - if this is >= 128 then the 16 bit value is PID_Data[0] ( NOT PID_Data[0] + ...

Let us know how it goes... Remote debugging is notoriously tricky :cry: I think the one piece of error checking it needs is to check the length of the message - if it's greater than 21 bytes then reset and start looking for MID again. As it stands - is the end isn't found then it will trample over m...

This was my first attempt.. It works in simulation for the 'dummy' data (one row of above table) - it assumes that the checksum condition is met to end the input... Output is a table of PIDs (PID[]) and a table of the data values for each PID (PID_Data[]) It assumes that PIDs of 0..127 have one byte...

We need to look at a 'slightly smarter' read - need a way to check the length of each data block and also when the end of the current data is received. This is the checksum byte - but how to know that this is the end of the data and not another PID? So it looks like PIDs are in a range of values (wi...

The length of the data blocks seems to vary - for example there are several starting 128, 84 with differing lengths..
Iain, kindly gave a link earlier - it looks like it is not as simple as waiting for 128 then reading a fixed number of bytes..

I think the checksum calculation is incorrect. If this fails then the display won't update. Need to sum all the bytes of the message (including the checksum byte) - it would be easier to use a loop here! - then take the 2s complement MOD 256 Final value compare to checksum byte... Don't have access ...

You need to use the escape character '\'

So your string will be .str = "AT+CUSD=1,\"100#\",15"

Martin