Header CRC in Freescale example for MCU : 16-bit MC9S12XF512MLM

Kartoon67 — Tue, 27 Mar 2012 16:09:11 GMT

Hi everybody,

I have some problem ton calculte the header CRC from a frame. For exemple, in the example freescale, the header CRC for a transmit frame SLOT09 is : 0x03FC.

When i calculate it, i find 0x2d7.

Caracteristic of the frame :

Header CRC = 0x03FC

Sync frame indicator : 1

Startup frame indicator : 1

ID : 9

Payload length : 16

So i have my frame is equal to that : 1100 0000 0100 1001 0000

I compute there with the polynomial sequence define in the Flexray criteria : 1011 1000 0101 (x^11 + x^9 + x^8 + x^7 +x^2 +1)

Why I don't find the same Header CRC?

Thank you in advance,

Best regards,

Re: Header CRC in Freescale example for MCU : 16-bit MC9S12XF512MLM

Kartoon67 — Wed, 28 Mar 2012 15:39:32 GMT

I have lerned by the Flexray Protocol specification that there is a specifical way to use the data from Header CRC.

By the documentation, i think that the data is composed by :

LSB Payload -> MSB Payload ->LSB FID -> MSB FID-> SU -> SY

Are here somebody who can say me that is it right or not? Because in any documentation by freescale, this calculation is really explain correctly...

Thanks in advance,

Regards,

S12 / MagniV Microcontrollers中的主题 Re: Header CRC in Freescale example for MCU : 16-bit MC9S12XF512MLM

Header CRC in Freescale example for MCU : 16-bit MC9S12XF512MLM

Re: Header CRC in Freescale example for MCU : 16-bit MC9S12XF512MLM