PEB2466 Просмотр технического описания (PDF) - Siemens AG

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PEB2466

Four Channel Codec Filter with PCM- and µ-Controller Interface SICOFI®4-µC

Siemens AG 

PEB 2466

Functional Description

2.2 The PCM-interface

Two serial PCM-interfaces are used for the transfer of A- or µ-law compressed voice

data. The PCM-interface consist of 8 pins:

PCLK:

FSC:

DRA:

DRB:

DXA:

DXB:

TCA:

TCB:

PCM-Clock, 128 kHz to 8192 kHz

Frame Synchronization Clock, 8 kHz

Receive Data input for PCM-highway A

Receive Data input for PCM-highway B

Transmit Data output for PCM-highway A

Transmit Data output for PCM-highway B

Transmit Control Output for PCM-highway A, active low during transmission

Transmit Control Output for PCM-highway B, active low during transmission

The Frame Sync FSC pulse identifies the beginning of a receive and transmit frame for

all of the four channels. The PCLK clock is the signal to synchronize the data transfer on

both lines DXA (DXB) and DRA (DRB). Bytes in all channels are serialized to 8 bit width

and MSB first. As a default setting, the rising edge indicates the start of the bit, while the

falling edge is used to latch the contents of the received data on DRA (DRB). If the

double clock rate is chosen (twice the transmission rate) the first rising edge indicates

the start of a bit, while the second falling edge is used for latching the contents of the

data line DRA (DRB) by default.

The data rate of the interface can vary from 2 × 128 kbit/s to 2 × 8192 kbit/s (2 highways)

A frame may consist of up to 128 time slots of 8 bits each. In the Time Slot Configuration

Registers CR5 and CR6 the user can select an individual time slot, and an individual

PCM-highway, for any of the four voice channels. Receive and transmit time slots can

also be programmed individually. An extra delay of up to 7 clocks, valid for all channels,

as well as the sampling slope may be programmed (see XR6).

When the SICOFI-4-µC is transmitting data on DXA (DXB), pin TCA (TCB) is activated

to control an extra external driving device.

Semiconductor Group

18

02.97

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