In imx233 documentation
The SPI bus is inherently a full-duplex bidirectional interface. However, the i.MX23 has a single DMA channel for SSP; therefore, the SSP must be programmed for either transmit or receive. In receive mode, the SSP continuously transfers the word written to its data register. In transmit mode, the SSP ignores incoming data.
i need to communicate with SPI half duplex means how to start, can anybody help on this