Owners manual

Interfaces

Figure 8-15. Frame/block format

Figure 8-16. Biphase-Mark Encoding

8.7.2.5. Operation Modes

The software operation of the OWA is divided into five steps: system setup, OWA initialization, the channel setup, DMA

setup and Enable/Disable module. These five setups are described in detail in the following sections.

8.7.2.5.1. System setup and OWA initialization

The first step In the OWA initialization is properly programming the GPIO. Because the OWA port is a multiplex pin. You

can find the function in the pin multiplex specification. The clock source for the OWA should be followed. At first you

must reset the audio PLL in the CCU. The second step, you must setup the frequence of the audio pll. After that, you

must open the OWA gating. At last, you must open the OWA bus gating.

After the system setup, the register of OWA can be setup. At first, you should reset the OWA by write 1 to OWA_CTL[0]

and clear the TX/RX FIFO by write 1 to register OWA_FCTL[17:16]. After that you should enable the globe enable bit by

write 1 to OWA_CTL[1] and clear the interrupt and TX/RX counter thought the OWA_ISTA and SP_TXCNT/SP_RXCNT.

8.7.2.5.2. The channel setup and DMA setup

The OWA support three methods to transfer the data. The most common way is DMA, the set of DMA can be found in

the DMA spec. In this module, you just to enable the DRQ.

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