Cypress EX-USB FX3 - Page 95

FX3 Programmers Manual, Doc. # 001-64707 Rev. *C 95
FX3 Application Structure
/* Enabling the callback for produce event. */
dmaCfg.notification = CY_U3P_DMA_CB_PROD_EVENT;
dmaCfg.cb = CyFxSlFifoUtoPDmaCallback;
dmaCfg.prodHeader = 0;
dmaCfg.prodFooter = 0;
dmaCfg.consHeader = 0;
dmaCfg.prodAvailCount = 0;
apiRetStatus = CyU3PDmaChannelCreate (&glChHandleSlFifoUtoP,
CY_U3P_DMA_TYPE_MANUAL, &dmaCfg);
if (apiRetStatus != CY_U3P_SUCCESS)
{
CyU3PDebugPrint (4, "CyU3PDmaChannelCreate failed, Error code =
%d\n", apiRetStatus);
CyFxAppErrorHandler(apiRetStatus);
}
/* Create a DMA MANUAL channel for P2U transfer. */
dmaCfg.prodSckId = CY_FX_PRODUCER_PPORT_SOCKET;
dmaCfg.consSckId = CY_FX_CONSUMER_USB_SOCKET;
dmaCfg.cb = CyFxSlFifoPtoUDmaCallback;
apiRetStatus = CyU3PDmaChannelCreate (&glChHandleSlFifoPtoU,
CY_U3P_DMA_TYPE_MANUAL, &dmaCfg);
if (apiRetStatus != CY_U3P_SUCCESS)
{
CyU3PDebugPrint (4, "CyU3PDmaChannelCreate failed, Error code =
%d\n", apiRetStatus);
CyFxAppErrorHandler(apiRetStatus);
}
■ The DMA channel transfers are enabled
/* Set DMA Channel transfer size */
apiRetStatus = CyU3PDmaChannelSetXfer (&glChHandleSlFifoUtoP,
CY_FX_SLFIFO_DMA_TX_SIZE);
/* Set DMA Channel transfer size */
apiRetStatus = CyU3PDmaChannelSetXfer (&glChHandleSlFifoPtoU,
CY_FX_SLFIFO_DMA_TX_SIZE);
8.1.2.8 DMA Callback
In this example, there are two data paths
■ U to P
■ P to U
A DMA callback is registered for the DMA Produce Events on each path. This event will occur when
a DMA buffer is available (with data) from
■ The USB OUT endpoint
■ The GPIF-II socket
In the DMA callback, this buffer is committed, passing on the data to the