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Visitor slm_gmail
Visitor
221 Views
Registered: ‎07-21-2018

Okay, here's a question about Zynq VDMA's - Buffer Descriptors and Parameters

So I'm here trying to implement a VDMA in a Zynq, and I came across a HUGE number of questions, but let's address a couple simple ones:

 

1)  What the heck is a buffer descriptor?  Do I ever need to access these?  The api sets them up, but what are they?

2)  I'm using the vdma.c file created by Xilinx, and it has the code pasted below in it.  I don't have any of these parameters in my xparameters.h, maybe because the file I grabbed from the interwebs wasn't build for ZC702 I'm using.

/// WHAT I HAVE IN XPARAMETERS.H THAT SEEMS LIKE IT MIGHT BE CORRECT   --------------------------------------------------------
#define XPAR_PS7_DDR_0_S_AXI_BASEADDR 0x00100000
#define XPAR_PS7_DDR_0_S_AXI_HIGHADDR 0x3FFFFFFF

^ Is this the DDR memory that the VDMA is writing to and reading from???  Seems too generic a name.....

 

/// WHAT IS IN VDMA.C -------------------------------------------------------------------------

#ifdef XPAR_AXI_7SDDR_0_S_AXI_BASEADDR
#define DDR_BASE_ADDR XPAR_AXI_7SDDR_0_S_AXI_BASEADDR
#define DDR_HIGH_ADDR XPAR_AXI_7SDDR_0_S_AXI_HIGHADDR
#elif XPAR_MIG7SERIES_0_BASEADDR
#define DDR_BASE_ADDR XPAR_MIG7SERIES_0_BASEADDR
#define DDR_HIGH_ADDR XPAR_MIG7SERIES_0_HIGHADDR
#elif XPAR_MIG_0_BASEADDR
#define DDR_BASE_ADDR XPAR_MIG_0_BASEADDR
#define DDR_HIGH_ADDR XPAR_MIG_0_HIGHADDR
#else
#warning CHECK FOR THE VALID DDR ADDRESS IN XPARAMETERS.H, // DEFAULT SET TO 0x01000000
#define DDR_BASE_ADDR 0x00100000 //0x10000000
#define DDR_HIGH_ADDR 0x3FFFFFFF //0x20000000
#endif

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2 Replies
Moderator
Moderator
181 Views
Registered: ‎11-09-2015

Re: Okay, here's a question about Zynq VDMA's - Buffer Descriptors and Parameters

HI @slm_gmail 

I believe that if you read the following Video Series I wrote about the AXI VDMA, your questions will be answered:

Video Series 24: Using the AXI VDMA in Triple Buffer Mode

Video Series 25: Debugging issues on the AXI VDMA IP

Video Series 26: Examples of advanced uses of the AXI VDMA IP

If not, please set me know the remaining questions,

Regards


Florent
Product Application Engineer - Xilinx Technical Support EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**
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Moderator
Moderator
142 Views
Registered: ‎10-04-2017

Re: Okay, here's a question about Zynq VDMA's - Buffer Descriptors and Parameters

Hi @slm_gmail,

 

Is everything clear for you on this topic?

If your question is answered or your issue is solved, please kindly mark the response which helped you find a solution (click on "Accept as solution" button below the reply)

If this is not solved/answered, please reply to the thread giving more information on your current status.

Thanks and Regards,

Don't forget to reply, kudo, and accept as solution.

Xilinx Video Design Hub
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