send several flames,and ncread for respond

yeoh · ‎12-27-2007

i am new to in-can. i need to send 22 of data flames to ECU,and get the ECU respond. As attached are complete VB6.0 code.

i use this method to send all 22 data flames., and use ncwaitforstate,ncread to read the ECU respond. But, i couldn`t get it directly,

i need to place about 30seconds delay after the ncwrite, so that i can get the desire respond. i knew that this is not the right way to get the

respond,as the respond are expected return immediatly. i would expect respond from ECU without such a long delay. Anyway one, please advice. Thanks

For y = 0 To 21 Step 1

        data = List2.List(x)
        Data_1 = Mid(data, 1, 2)
        Data_2 = Mid(data, 3, 2)
        Data_3 = Mid(data, 5, 2)
        Data_4 = Mid(data, 7, 2)
        Data_5 = Mid(data, 9, 2)
        Data_6 = Mid(data, 11, 2)
        Data_7 = Mid(data, 13, 2)
        Data_8 = Mid(data, 15, 2)

        x = x + 1

        Transmit.data(0) = "&H" & Data_1
        Transmit.data(1) = "&H" & Data_2
        Transmit.data(2) = "&H" & Data_3
        Transmit.data(3) = "&H" & Data_4
        Transmit.data(4) = "&H" & Data_5
        Transmit.data(5) = "&H" & Data_6
        Transmit.data(6) = "&H" & Data_7
        Transmit.data(7) = "&H" & Data_8

        Status = ncWrite(TxHandle, Len(Transmit), Transmit)
        wait 30s


Next y

   Status = ncWaitForState(RxHandle, (NC_ST_READ_AVAIL), 2000, State)
   If (CheckStatus(Status, "ncWaitForState") = True) Then GoTo Error

   Status = ncRead(RxHandle, Len(Receive), Receive)
   If (CheckStatus(Status, "ncRead") = True) Then GoTo Error

DirkW · ‎12-27-2007

The way to go is using the wait for state as you did in your code. Right now it has a timeout of 2000 ms configured. Try to remove the 30 seconds wait and adjust your timeout to 30000 ms. Now you should get the frame as well. Try to lower the timeout until you reach the minimum time your ECU needs to respond.

DirkW

yeoh · ‎12-28-2007

Thanks for replying.

i could get the respond by adding more delay. But, one problem occur. i need to read for 3 times,in order to get the desire respond.

As show in attached file. i try to read the respond for 6 times,after 22 flames was sent by using ncwrite. i couldn`t get the desire respond for the first time read, However, the desire respond can only get it after second times of read.

As show are the respond i get after sending 22 flames

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

0x91741780FFFF88BE --->previous respond for initialize download

0x91741780FFFF88BE ---->previous respond for initialize download

0x9176FFFFFFFFFFF ------>desire respond (showing the 22 flames has been written successfully)

''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

After that,i need to send a flames to inform ECU that all the data has finished written. Then, the ECU will calculate the checksum of all data i sent , lastly, will send respond a flame to indicate that the checksum(88BE) has correctly match the flames that i sent during initialize download section.

i am wondering whether i am using the correct method to send severals flames, but it works for sending one flame ,and then get a respond immediately. Please advice.

yeoh · ‎12-28-2007

Thanks for replying.

i could get the respond by adding more delay. But, one problem occur. i need to read for 3 times,in order to get the desire respond.

As show in attached file. i try to read the respond for 6 times,after 22 flames was sent by using ncwrite. i couldn`t get the desire respond for the first time read, However, the desire respond can only get it after second times of read.

As show are the respond i get after sending 22 flames

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

0x91741780FFFF88BE --->previous respond for initialize download

0x91741780FFFF88BE ---->previous respond for initialize download

0x9176FFFFFFFFFFF ------>desire respond (showing the 22 flames has been written successfully)

''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

After that,i need to send a flames to inform ECU that all the data has finished written. Then, the ECU will calculate the checksum of all data i sent , lastly, will send respond a flame to indicate that the checksum(88BE) has Not correctly match the flames that i sent during initialize download section.

The return checksum from ECU is zero. i am thinking why would the ECU has calculated zero checksum, Is it possible that the 22flames of data was not correctly send ??

i am wondering whether i am using the correct method to send severals flames, but it works for sending one flame ,and then get a respond immediately. Please advice.

MXI Master · ‎12-28-2007

Yeoh,

I was looking at your code and could not figure out where all of your 22 frames were being written. Then the responses that you are getting in return, are the first two responses possiblly just partial returns. What are you expecting, and why are you expecting that from your ECU.

How you send your frames depends on how your ECU is configured. It is possible that you are writting too much data to your ECU before it is ready to recive more data.

The more information you can send me on what you are expecting the better.

Cheers,

-Marshall R

yeoh · ‎12-28-2007

Marshall R,