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Chapter 9. Slave FIFOs Page 9-33

9.3.11 Auto-Mode Example: Asynchronous FIFO IN Data Transfers

The initialization code is exactly the same as for the synchronous-transfer example in Section

9.3.10, but with IFCLK configured for internal use at a rate of 48 MHz and the ASYNC bit set to 1.

Figure 9-45 shows the one-line modification that’s needed.

Figure 9-45. TD_Init Example, Asynchronous Slave FIFO IN Data Transfers

Code to perform the transfers is, as before, unnecessary; as Figure 9-46 illustrates.

Figure 9-46. TD_Poll Example, Asynchronous Slave FIFO IN Data Transfers

9.4 Switching Between Manual-Out and Auto-Out

Because OUT endpoints are not automatically armed when the FX2 enters Auto-Out mode, the

firmware can safely switch the FX2 between Manual-Out and Auto-Out modes without any need to

flush or reset the FIFOs.

TD_Init( ): // slight modification from our synchronous firmware example

IFCONFIG = 0xCB;

// this defines the external interface as follows:

// use internal IFCLK (48MHz)

// use slave FIFO interface pins asynchronously to external master

TD_Poll( ):

// nothing! The FX2 is doing all the work of transferring packets

// from the external master async interface to the endpoint buffer…

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