I got a circuit to work with AD9910 with STM32 controller from someone else. It is working great. But I am trying to trace how the connection will be between AD9910 and the micro. I saw something confusing. The micro use SPI to transfer data to DDS. In the datasheet, 4 lines used for SPI in 9910 is pin 67 ( SDIO), pin 68 (SDO), pin 69 (SCLK) and pin 70 (NOT CS). The STM32 has the corresponding pin MISO, MOSI, SCK and NSS as well. However, when I trace the connection, I find that those pins are connecting to some pins other that the one I mentioned.
For example, (STM)32NSS <-> (AD9910)pin 31 D12
(STM32)SCK <-> (AD9910) pin 27 D13
(STM32)MISO <-> (AD9910) pin 26 (D14)
I check that carefully and I think the map is correct. But I don't understand how SPI work if they go to different pin in AD9910.