Memory write/read problem

fan li3

Hi TI engineers,

We are using C6678 EVM connected to a PC host whose operation system is windows XP. We write data to DDR beginning with the address 0x90000000 and then read the data from the same address referring to mcsdk_2_01_02_06\tools\boot_loader\examples\pcie\linux_host_loader\pciedemo.c (writeDSPMemory and readDSPMemory). The data read using method is right but if we use the memory browser in CCS5 to view the data written into DDR from the address 0x90000000, the data is wrong.

Could you please find out the problem and give us some advice?

Thanks in advance!

over 9 years ago

0 Ganapathi Dhandapani95 over 9 years ago

TI__Mastermind 28085 points

Hi Fan,

The reason for this behavior is translate the memory access in the range 0x8000 0000 - 0xFFFF_FFFF (32-bit addr) to the range 0x8 0000 0000 - 0x8 FFFF_FFFF (36-bit addr). This is configured through the MPAX registers of the DSP Extended Memory Controller (XMC).

If you need more information on the MPAX configuration please refer Section 7.3.1 and 7.3.1.3 in "TMS320C66x DSP CorePac User Guide".

http://www.ti.com/lit/sprugw0c

Thanks,

0 Chris Jagielski over 9 years ago in reply to Ganapathi Dhandapani95

Expert 1630 points

Hi Ganapathi,

I'm having this same issue, except at 0x80000000. I'm also using the 6678EVM, like Fan.

Using the TI debugger on the EVM for printf's, if I write to DDR like this I see the result.

*(volatile int *)0x80000030 = 0xface0ace;
volatile int face0ace2 = *(volatile int *)0x80000030;
printf("check DDR value = %h\n", face0ace2);

But when I look at the address in the CCSv6 Memory Browser, it shows 0's everywhere.

What could be causing this inconsistency?

0 Ganapathi Dhandapani95 over 9 years ago in reply to Chris Jagielski

TI__Mastermind 28085 points

Hi Chris,

I think DDR is not configured properly on your setup. After loading the gel file please check DDR configuration register on memory browser. I have tested your code on C6678 EVM, it is working fine.

Thanks,

0 Chris Jagielski over 9 years ago in reply to Ganapathi Dhandapani95

Expert 1630 points

Excellent - thank you for your help! You are right, I have it configured correctly now and it works like I expect it.

Thanks again

0 Ganapathi Dhandapani95 over 9 years ago in reply to Chris Jagielski

TI__Mastermind 28085 points

Thanks for your update.

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Memory write/read problem