Rappid error - cannot boot from CAN with autobaud

[kimjin]

Hi,

i got a message " loss communication with BAM, check password or verify boot configuration setting ABS2=1 ABS0=0 FAB=1. please cycle power and try again. object reference not set to an instance of an object".

Could anybody please explain what it means?

my device is MPC5675K using the default password. and i am sure my ABS2=FAB=1 (they are tied together) and ABS0=0.

i observed the CAN0_RXD had the messages from the host but no response on CAN0_TXD.

thanks.

[cenközer]

Hi,

I have exactly the same problem that kimjin had before. I am sure about FAB,ABS configuration, i can observe incoming signals however there is no response from MPC5675K MCU. I also tried the what kimjin says about pulling LIN0_TXD high but result did not change. I am using MPC5675KEVB. I would be very appreciated if you recommend something about the issue, thank you.

[gmgunderground]

In these days I'm working too on CAN Serial Boot and I have found that not all MPC has the auto baud. Have you checked the datasheet if you can use auto baud or use a fixed CAN speed ? On MPC5554 CAN speed for serial boot is fixed at 200K

[kimjin]

gmgunderground,

thank you for your response. you are so nice.

i have checked the datasheet and am sure MPC5675K supports the auto baud CAN boot.

and i also found the root cause. in auto baud mode, the MicroP will monitor both LIN and CAN at the same time to decide which way it will boot from. the user has to keep the LIN inactive if he want to use CAN boot and in some other MPCxx errata file, it reminds the user to pull TXD high (not NC, not low) to keep the LIN module inactive. unfortunately, this requirement is not in 5675K's datasheet or RM,  and i wasted days time to find the cause. i would like to say freescale is lossing its patience to create good Manual to include the detailed information.