66AK2L06: AB-synchronized 3D transfer using EDMA3

Hi,

Several things to checks:

1.  >>>>>>a large block of data - 1.125 Gbyte.>>>>>>>> I have an array with 301989888>>>>>>>

So, ACNT = 4;  //size of each element

BCNT = 6144; //number of elements in 1 frame

CCNT = 49152; // number of frames

To best use the EDMA, it is good to set ACNT = 128 or 64, that is the DBS (data burst size) of the EDMA transfer controller, although ACNT=4 should work, it is not efficient.

2. You used CCNT=49152, will change this to anything less than 32768 work for 100% transfer completion? I knew ACNT, BCNT, CCNT can be 0 to 65535, but I met some issues in the past for BCNT over 32768, only partially transmitted (didn't debug further). So I am not sure if CCNT > 32768 in your case caused any issue?

3. How do you know the transfer didn't finish? For example, look at the memory from CCS or check with the code (you need to do cache invalidate after EDMA transfer, or look at the non-cache view) or the IPR/IPRH didn't set?

4. If transfer stuck, do you see any error in ERRSTAT and ERRDET registers?

5. >>>>>>>But even for 160000 elements it doesn't work, transfer freezes on 60-70%.>>>>>>> Let's focus on this smaller transfer. What is the ACNT, BCNT, CCNT settings? Or you can share the PaRamSet programmed for this transfer? In most tests, we use CCNT=1, ACNT * BCNT is already big enough for a typical transfer. I am sure that we did transfer size of several MB without any issue. Will CCNT=1 works for this?

6. For 160,000 x 4 = 640KB transfer, this is very small, if you change the SRC, DST (like L2, MSMC or DDR3) and EDMA channel controllers or transfer controllers, do they all fail?

Regards, Eric

Hi,

Thanks a lot for your reply!

1. Thank you for the advice. I'll keep that in mind.

2. I tried to use CCNT<32768. The transfer didn't end also..

3. For looking at the memory I use memory browser in CCS and non-cached memory.

4. ERRSTAT = 0x00000008; ERRDET = 0x00000000.

5. For 160000 elements I used : ACNT = 4; BCNT = 400; CCNT = 400; Transfers of different sizes of data (for example even for 500Mb) works correctly for CCNT = 1.

6. It doesn't depend on it. And I need 1.125 Gb transfer, so I can't use L2, MSMC, only DDR3.

Do you have any other ideas?

Regards, Kirill

Hi,

>>>>>ERRSTAT = 0x00000008; ERRDET = 0x00000000.>>>>> This didn't provide any useful information.

So you verified that when CCNT=1, there is no issue to transfer a big block even 500Mb. How do you trigger the next transfer if CCNT > 1? It looks CCNT > 1 stuck in the middle.

If ACNT = 0x6000 and BCNT= 0x6000 works in your case, it can transmit 576MB already, will a linked transfer work for your purpose (you can use 2 linked together with CCNT=1 for 1.125GB)?

Regards, Eric  

Hi,

Thank you for activity:)

I trigger next transfer manually, using a cycle with CCNT iterations.

I've already thought about linked 2D transfers. What do you think will be faster: two linked 2D transfers, or 3D transfer?

Regards, Kirill

Hi,

>>>>two linked 2D transfers, or 3D transfer.>>>>I thought the speed would be the same. You need to make ACNT integer multiple of 128 or 64. The speed will be impacted by which EDMA CC and TC used, not because of 2 linked 2D or 1 3D transfer.

Regards, Eric