How to configration the MPC8245 when it works in 32-bit data bus mode

[xuchaoli]

I made a board based in MPC8245,and I use to 16-bit SDRAM compose 32-bit RAM ,connect the MDL[0] to GND,MPC 8245 works in 32-bit data bus mode ,.When I write data to SDRAM，if the address is ended by 0x0 、0x8,like 0x00001000,0x00002008,they correct.but if the address is ended by 0x4、0xc,the data is all 0s.when I observe the data bus using oscilloscope,the data bus is 0; If I do some thing wrong ? about the connection of the MPC8245 and the SDRAM? the address bus is wrong ? My initialization configration file is some wrong ? the USB TAP 、CodeWarrior and MPC8245 is not compatible? What should I pay more attention to？

Thanks a lot

[lunminliang]

Hello xuchao li,

One more question, did you write the SDRAM data in CCS or CodeWarrior?

Regards

Lunmin

[xuchaoli]

I have made a case,the number is 00065430.Thanks.

[lunminliang]

Got that. Please check your registered mail box.

[xuchaoli]

Hello Lunminliang,

Thanks for your help.

I  write the SDRAM data in CodeWarrior. Becasue I can only access MPC8245 by  CodeWarrior + USB TAP.

The MCCR1[DBUS_SIZ] are read only bits.I write this bits with the value of my hardewave defiend(DL[0] = GND).I have tested it like this:I use the Codewarrior to write 8 bytes data to SDRAM, I observe the /WE using oscilloscope.The /WE signal awayls two two times low level.Perform one write command,/WE signal  two times low(one for precharge,one for werite). when I write 8 bytes(64bits) data ,It Perform two times.,so the MPC8245 must works in 32-bit mode. If in 64 bit mode ,is only once .

I can't read the data of the configration registers by Codewarrior.

MCCR1[ROW] = '00', is indicates that the ROW of the SDRAM is 13 or 12,and my SDRAM(IS42S16800F) is 11 rows by 9 columns by 4 logical banks.

I have being learned how to use the "tech support case ",but I can't use it now,so ,I am sorry ,I can only communacte with you by this way.I will try my best to stady the "tech support case ".

The critical question is the data in local data bus is 0 ,when I write data in x00001004,0x0000200c(and so on ) using CodeWarrior + USB TAP.

Thanks.

[lunminliang]

Hello xuchao li,

The MCCR1[DBUS_SIZ] are read only bits.I write this bits with the value of my hardewave defiend(DL[0] = GND).

>>Yes, it's read only, as it indicates the bus width and determined by reset cfg signal , you can check this to verify.

BR

Lunmin

[lunminliang]

Hello xuchao li,

Please examine the MCCR1 on your MPC8245 system. MCCR1[DBUS_SIZ] indicate the SDRAM bus to be 32b or 64b. MCCR1[ROW] configure the row number of the SDRAM memory which have to meet with the specification of the SDRAM chips on the MPC8245 system.

Have a great day,
Lunmin

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[lunminliang]

Hello xuchao li,

Please kindly let me know the case number if you have done that. Thanks.

BR

Lunmin

[lunminliang]

Hello xuchao li,

In the MPC8245UM.pdf, there are some unsupported multiplexed mode, please check if your case is one of them.

Also please provide your schematic for investigation, thanks.  If it's not convenient to share on this public community, you could submit a tech support case on www.nxp.com and asking for assigned to me. (As you seems have not ever done that before I could not find your information to create case for you ). Please refer to the steps below for that:

How I could create a Service Request?

Have a great day,
Lunmin

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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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