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AMBE-3000F™ Vocoder Chip Users Manual

Version 3.4, April, 2014

O Management

Voc

oder Chip. When in packet mode the AMBE-3000F™ Vocoder Chip no longer outputs channel packets automatically

every 20 ms and the codec interface is inactive.

5.5 SPI Interface

The serial peripheral interface (SPI) is a high-speed, synchronous serial I/O port that can be used as the speech interface to the

codec. This interface allows a serial bit stream to be transferred between the AMBE-3000F™ Vocoder Chip and an audio

codec. The interface includes four-pins. The SPI interface is designed for speech data only and may be used only in codec

mode.

TQFP BGA

Pin Name Direction Description

27 K2 SPI_CLK Input A/D Serial clock.

28 K4 SPI_STE Input

The framing signal generated from

SPI_GENSTE.

31 M1 SPI_RX_DATA Input

PCM Data from A/D Converter to AMBE-

3000F™ Vocoder Chip

32 N1 SPI_TX_DATA Output

PCM Data from AMBE-3000F™ Vocoder

Chip to D/A Converter

Table 17 SPI Interface Pins

Figure 30 SPI Timing

The SPI_STE signal is asserted low at least 136 ns before the valid SPI_CLK edge and remains low for at least 136 ns after the

receiving edge of the last data bit.

MIN MAX

SPI_CLK Cycle time (t

SPI

) 272 ns 7.8 µs

SPI_CLK low Pulse duration (t

) 126 ns 3.9 µs

SPI_CLK high Pulse duration (t

) 126 ns 3.9 µs

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