BAM update Problem (CAN)

[youngguekim]

Hi. I am using MPC5644A

I want to update a Firmware using BAM(eSCI).

But When i am receiving CAN_A message continually, I can;t update

For example, I receive CAN message like Figure. 1

There is no BAM echo message (0xFEEDFACE)

and When CAN_L, CAN_H pin are short, BAM works well

I can't understand that CAN_A message'ID I recieved is not 0x00, 0x01, 0x02, 0x03, 0x11, 0x12, 0x13

Help me please

Figure 1.

[lukaszadrapa]

Hi,

just a quick question - do you use fixed baud rate or baud rate detection?

Regards,

Lukas

[youngguekim]

Hi.

I am using baud rate detection (115200bps)

[lukaszadrapa · Accepted solution]

Well, then it makes sense. There shouldn't be any traffic on CAN_A because (copied from reference manual):

Lukas

[youngguekim]

Thank you.

if I use Fixed Baud rate(eSCI) for Download. Can be any traffic On CAN_A ?

I can't remove CAN_A message from other ECU

[lukaszadrapa]

Yes, but there can't appear a message with 0x11 ID:

Lukas

[youngguekim]

Thank you very much

I have only 1 Question.

when I use Fixed Baud rate (9600bps, crystal frequency : 8MHz),  I can't receive echo message(0xCAFEBEEF)

do you know what is problem??

1. Fixed Baud rate

2. Baud rate Detection (Nomal)

[lukaszadrapa]

Is a delay between characters long enough? We can't send next character to device until BAM finishes transmission of echo character. If the baud rate is 9600 bps, 10 bits (start bit + 8 data bits + stop bit) are transmitted in 1.04ms. If we add some time for software overhead, the delay between characters should be about 1.1ms or 1.2ms, at least. Could you check that?

It doesn't explain why it works when baud rate detection is used but I can't see other reason.

Lukas

[youngguekim]

Delay between characters is long enough (above 0.5s)

it's better to use Detection mode.

Thank you for your help. Lukas Zadrapa

1. Fixed

2. Detection

[lukaszadrapa]

I did quick test on my board and it works as expected:

Once all data are sent, the BAM starts execution of downloaded program and stops sending of echo characters (0xAA character is used just for test).

Lukas

[youngguekim]

Thank you.

you did a test in fixed Baud rate and Your Clock circuit is same as Picture(XTAL : 8MHz)?

[lukaszadrapa]

Yes, I have 8MHz crystal.

Have you pulled EVTO pin up? You can use 5-10kohm resistor.

I tried to pull it down for test purposes and I can see that BAM returns only FEEDFACE in this case. So, this could be the reason.

Lukas

[youngguekim]

when I use Fixed mode, EVTO pin -> OPEN

when I use Detection mode, EVTO pin -> Short

you mean, When I use Fixed mode, I have pulled EVTO pin up (5~10kohm)?

I will try..

[lukaszadrapa]

EVTO is not pulled up internally:

So, you have to pulled it up by external resistor...

Lukas