Sony Ericsson GM47, GM48 manual bit data word format

2. SYSTEM CONNECTOR INTERFACE

2.7.1 PCM Data Format

All of the module’s PCM signals, including signals between its CODEC and DSP conform to the PCM data I/O format of the industry standard DSP from Texas Instruments.

PCMCLK (bit clock) and PCMSYNC (frame syncronisation) are both generated by the DSP within the module.

The DSP within the module is the master therefore all external PCM clocks and data from external devices must be synchronized to it

13-Bit PCM Mode

BitContents

D15 to D14 Equal to D13

D13 to D1 Two's complement of the 13-bit PCM

D0 LSB, not used

The module implements 13-bit PCM with the 13-bit data embedded in a 16-bit word within a 24-bit frame (see Figure 2.6). Each PCM word contains 16-bits: D0 to D15. D13 to D1 is the two’s complement value of the 13-bit PCM, with D13 as the sign bit. D14 and D15 are always set to be equivalent with D13. D0, the LSB, is not used as shown in Figure 2.5 below.

= D13 13 bit PCM D0

MSB D14 D13 D12 D11 D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

LSB

16 bit data word

Figure 2.5 16-bit data word format

16-Bit PCM Mode

BitContents

D15 - D0 Two's complement

The frame format is equal to the one shown in Figure 2.5, but with D15, D14 and D0 filled with significant bits. D0 is the two’s compliment value of the 16-bit PCM with bit 15 as the sign bit.

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LZT 123 7263 R1C