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DMA buffer size | Cypress Semiconductor

DMA buffer size

Summary: 3 Replies, Latest post by Ayi on 21 Aug 2012 08:41 PM PDT
Verified Answers: 0
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Ayi's picture
31 posts

With usb 3.0 mode .   dmaSlFifoConfig.size = size * 16; it  doesn't work ,the size is 1024 .But if change to       dmaSlFifoConfig.size = size/2; it works but the speed only 8M around .how can i solve the problem ,I am hurry it .

develop with sdk v1.2 . 

 /* Create a DMA MANUAL Channel between P-port producer socket and U-port consumer socket */

            //dmaSlFifoConfig.size = size  * 16;

            dmaSlFifoConfig.size = size;

            dmaSlFifoConfig.count = CY_FX_SLFIFO_DMA_BUF_COUNT;

            dmaSlFifoConfig.prodSckId = (CyU3PDmaSocketId_t)(CY_FX_EP_PRODUCER_PPORT_SOCKET);

            dmaSlFifoConfig.consSckId = (CyU3PDmaSocketId_t)(CY_U3P_UIB_SOCKET_CONS_0 | CY_FX_EP_CONSUMER_USB_SOCKET);

            dmaSlFifoConfig.dmaMode = CY_U3P_DMA_MODE_BYTE;

            dmaSlFifoConfig.notification = 0;//CY_U3P_DMA_CB_PROD_EVENT;

//            dmaSlFifoConfig.cb = CyFxSlFifoPtoUDmaCallback

            dmaSlFifoConfig.cb = NULL;

            dmaSlFifoConfig.prodHeader = 0;

            dmaSlFifoConfig.prodFooter = 0;

            dmaSlFifoConfig.consHeader = 0;

            dmaSlFifoConfig.prodAvailCount = 0;

            /* Create the channel */

            apiRetStatus = CyU3PDmaChannelCreate (&glChHandleSlFifoPtoU,



Lumpi6's picture
341 posts

Hi Ayi,


sounds like your application has not enough free RAM. I think cypress changed something in the Version 1.2 so from 0x40078000 to 0x40080000 are 32KB reserved for bootloader. May be now you can not allocate that much DMA memory. I think in the release notes of Versioin 1.2 it says that space is for bootloader and if you do not use it, then you can change the value back to 0x40080000.



Ayi's picture
31 posts

hi Lumpi6 Thanks for your replay ,I noticed the size 0x4008000,But cypress change the size and then it is some reason.How can I change to make the DMA transfer tuth supper speed .can you help me 

Ayi's picture
31 posts

 Hi Lumpi6


I change the size back to 0x4008000 and it doesn't work too.So i think it isn't the toot  of the problem.And if I change the file cyfxapi.a back to sdk v1.1 then it work well.So can you take me out of the issue. I am hurry it .

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