how can i wakeup TJA1040 use CAN

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how can i wakeup TJA1040 use CAN

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xsfan
Contributor I

i need to wakeup a TJA1040 through CAN and i found the tBUS value is (0.5us~5us),so when i use the 500kbit/s CAN ,it means that any one bit in the message will cost 2us,and may lead to generate a wakeup signal(if the value is fit).

so,it means that any message on the bus will wake up the TJA1040,am i understand right?

but if on the car,the meter will send some messges all the time (even if IGN OFF),so during the standby mode the TJA1040 will always receive a wakeup signal,and then(MCU) wake up the TJA1040 ,so the TJA1040 stand by mode seems do  not work .

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lukaszadrapa
NXP TechSupport
NXP TechSupport

Hi,

yes, that's correct. Any message on CAN bus will lead to wake up in this case.

If it is not suitable behavior for your application, there are other transceivers like TJA1041A or TJA1044:

http://www.nxp.com/documents/data_sheet/TJA1041A.pdf 

See the "7.1 Wakeup via bus":

http://www.nxp.com/documents/application_note/AN00094.pdf 

And

http://www.nxp.com/documents/data_sheet/TJA1044.pdf 

("7.2 Remote wake-up (via the CAN bus)")

Regards,

Lukas

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