Siemens AC75 Dokumentacja Pobierz pdf (Strona 71)

AC75 Hardware Interface Description

Strictly confidential / Preliminary

AC75_HD_V00.202 Page 71 of 120 27.04.2006

The timing of a PCM short frame is shown in Figure 29. 16-bit data are transferred in both

directions at the same time during the first 16 clock cycles after the frame sync pulse. The

duration of a frame sync pulse is one BITCLK period, starting at the rising edge of BITCLK.

TXDAI data is shifted out at the next rising edge of BITCLK. Data transmitted from RXDAI of

the internal application is sampled at the falling edge of BITCLK.

BITCLK

TXDAI

RXDAI

MSB

LSB

14 13

MSB

125 µs

Figure 29: Short Frame PCM timing

The timing of a PCM

long frame is shown in Figure 30. 16-bit data are transferred in both

directions at the same time during the frame sync pulse FS is high. For this reason the

duration of a frame sync pulse is 16 BITCLK periods, starting at the rising edge of BITCLK.

TXDAI data is shifted out at the same rising edge of BITCLK. Data transmitted from RXDAI of

the internal application is sampled at the falling edge of BITCLK.

BITCLK

TXDAI

RXDAI

MSB

LSB

14 13

MSB

125 µs

Figure 30: Long Frame PCM timing

1 2 ... 66 67 68 69 70 71 72 73 74 75 76 ... 119 120

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Siemens AC75 Dokumentacja Strona 71