I am still in the process of contemplating buying the seeedstudio CAN bus shield.
Essentially I want to make sure that I am able to listen for a very specific can bus message in my car.
The car’s onboard climate control computer sends a request on the CAN bus when ever A/C compressor activiation is requested.
It is this message I want to intercept.
I did successfully identify the message using a cheap OBD2-USB adapter (elm327) along with hyperterminal for windows.
so I used the following AT commands for init:
ATSP6 (ISO 15765-4 CAN (11 bit ID, 500 kbaud))
and the filter command itself:
issuing a ATMA command then gives me the following hex values:
AC Request ON MSG: 374 XX 32 YY (32 = AC on)
AC Request OFF MSG: 374 XX 22 YY (22= AC off)
note: XX and YY indicates bytes that I dont care about.
as you have guessed I want to exactly filter out messages where I want to :
listen for transmitter with id = 374
listen for incoming bytes that match the value “32” at position 6.
how would I construct my init filter call for this example ?