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I am developping an Android app which will display CAN data using an ELM 327 in Bluetooth. Following the ELM 327 Datasheet, I can filter the received data by sending AT CRA hhh (hhh = CAN ID) before monitoring with AT MA. My objective is to display data from specific CAN IDs (for example 7A2, 250, 420...). I try to send many AT CRA hhh commands but just the last one is used by ELM. My question is: how can I set many CAN ID filters to the ELM327?

The ELM also accepts CAN filter and a maks commands with AT CF and AT CM, is it the solution?

Oier Etchelecou
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CRA hhh is a convenient way to set easily a mask and a filter allowing to receive messages with a single CAN ID.

For example,

AT CRA 123

is equivalent to

AT CF 123
AT CM 7FF

So, yes, you are right, to receive a list of specific CAN IDs, you have to use the AT CF and AT CM commands and forge a specific (filter,mask) pair according to your needs.

Pierre
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    Assume I want to filter a specific CAN ID 123, can you tell me how to do that? I have used AT CRA 123 and AT MA together, but the result shows all can messages are displayed.... – Sunny Lei Oct 05 '17 at 06:39
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    I want to filter (receive) CAN IDs 0x12A ans 0x174 (for example)- could you please give an example how to achieve that in ELM327? – theangrylama Jul 03 '19 at 13:13