ST STM32F446 Series

SPDIF receiver interface (SPDIFRX) RM0390
898/1328 RM0390 Rev 4
Figure 338. SPDIFRX block diagram
1. ‘n’ is fixed to 4.
27.3.1 S/PDIF protocol (IEC-60958)
S/PDIF block
A S/PDIF frame is composed of two sub-frames (see Figure 340). Each sub-frame contains
32 bits (or time slots):
• Bits 0 to 3 carry one of the synchronization preambles
• Bits 4 to 27 carry the audio sample word in linear 2's complement representation. The
most significant bit (MSB) is carried by bit 27. When a 20-bit coding range is used, bits
8 to 27 carry the audio sample word with the LSB in bit 8.
• Bit 28 (validity bit “V”) indicates if the data is valid (for converting it to analog for
example)
• Bit 29 (user data bit “U”) carries the user data information like the number of tracks of a
Compact Disk.
• Bit 30 (channel status bit “C”) carries the channel status information like sample rate
and protection against copy.
• Bit 31 (parity bit “P”) carries a parity bit such that bits 4 to 31 inclusive carry an even
number of ones and an even number of zeroes (even parity).
Figure 339. S/PDIF Sub-Frame Format
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