Try this line right after SPI.setDataMode ...
SPI0->SPI_CSR[0] = SPI0->SPI_CSR[0] & 0xFFFFFF; // clear delay between consecutive transfers (DLYBCT = 0)
Note: The default (DLYBCT = 1) keeps CS enabled for 32 MCLK after a completed transfer. Some device needs that for working properly (from spi.cpp).