PT=B_0x0
SPDIFRX data input register
| DR | data value  |  
| PE | parity error bit  |  
| V | validity bit  |  
| U | user bit  |  
| C | channel status bit  |  
| PT | preamble type 0 (B_0x0): not used 1 (B_0x1): Preamble B received 2 (B_0x2): Preamble M received 3 (B_0x3): Preamble W received  |