Digital Voice Systems VC-20-ATC-10B Especificaciones descargar pdf (Pagina 74)

FAA20 Embedded NEXCOM Vocoder

Board Manual

This manual has been prepared for the Federal Aviation Administration.

FA100-00107 (March 2004) – Rev 1.0.0 Page 68

8.3.5 CLKRATE

The CLKRATE command sets/gets the PCM and NIB interface clock rates

used when internal interface timing is enabled. Two different rates can be

assigned for each interface: one for normal timing mode and one for

truncated timing mode.

Table 16: CLKRATE Command Syntax

ATTRIBUTE DESCRIPTION

SYNTAX CLKRATE [interface [tmode [rate]]]

interface PCM Selects the PCM interface

NIB Selects the NIB interface

tmode NORM Selects normal timing mode

TRUN Selects truncated timing mode

PARAMETERS

rate Des ired clock rate (Hz) entered as a decimal integer.

FLASH YES

Print current clock rate settings.

COM1: clkrate

> CLKRATE PCM NORM = 3840000

> CLKRATE PCM TRUN = 3840000

> CLKRATE NIB NORM = 9600

> CLKRATE NIB TRUN = 9600

Print PCM clock rate settings.

COM1: clkrate pcm

> CLKRATE PCM NORM = 3840000

> CLKRATE PCM TRUN = 3840000

EXAMPLES

Change NIB clock rate settings for the truncated timing mode.

COM1: clkrate nib trun 8000

> CLKRATE NIB TRUN = 8000

The FAA20 uses the processor’s Multi-channel Buffered Serial Ports

(MCBSPs) to generate interface timing; therefore, clock rates are limited to

values that can be generated using the processor execution clock and a

fixed number of dividers. Note: When external timing is provided, these

limitations do not apply. The FAA20 software automatically determines if

the requested rate can be generated. If the rate cannot be generated, a

parameter error message is printed.

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Digital Voice Systems VC-20-ATC-10B Especificaciones Pagina 74