Digital Voice Systems VC-20-ATC-10B Specifikace stáhnout pdf (Strana 47)

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 41

Table 8: Thread List

THREAD ↓ DESCRIPTION

RESET_HWI* 1 LED #1 (red). Typically indicates peak audio events.

NTX_HWI 2 Transmit Nibble Interrupt. This thread writes nibble data to nibble

interface. It also triggers the ENC_SWI based on data produced

by a vocoder synchronizing function which monitors unit

configuration and the position of the FMEN signal conductor. This

thread is triggered at the falling edge of the ENCCK signal

conductor, i.e. every 106 us (normal timing mode).

NRX_HWI 3 Receive Nibble Interrupt. This thread reads nibble data from

nibble interface. It also triggers the DEC_SWI as soon as a voice

packet is com pletely received. This thread is triggered at the

falling edge of the DECCK signal conductor, i.e. every 106 us

(normal timing mode).

TMR_HWI* 4 Timer Interrupt. This interrupt is managed by the DSP/BIOS.

AUD_HWI 5 Audio Codec Interrupt. This interrupt accesses the MCBSP #0

serial port data holding register. It is triggered when an entire data

sample has been received, i.e. every 125 us (normal timing). It

transfers both RX and TX data.

DIG_HWI 6 Digital PCM Interrupt. This interrupt accesses the MCBSP #1

serial port data holding register. It is triggered when an entire data

sample has been received, i.e. every 125 us (normal timing). It

transfers both RX and TX data.

RAT_SWI 7 Rate Adapter Interrupt. This interrupt performs data rate

adaptation when it is enabled. Otherwise, it passes the data

through unaltered. When the rate adapter is enabled, it is

triggered after the DIG_HWI thread after 6 samples are collected;

otherwise, it is triggered after 5 samples are collected.

LVP_SWI 8 Linear Voice Processor. This thread executes all linear voice

processing functions including the mixer, GAM, and activity

detection. Note: The TEST signal functions (like FFT, TONDET,

and SWEEP) are run in the CMD_TSK after a sufficient amount of

data is collected in the COM queue. The LVP_SWI interrupt is

triggered by the AUD_HWI or DIG_HWI when CLKREF is set to

AUD or PCM, respectively. It is triggered for once for every 5

samples.

CVR_SWI n/a Packet Voice Router. This thread is presently implemented as

function, i.e. it is not a true thread. It is called by other threads, i.e.

NTX_HWI, NRX_HWI, ENC_SWI, and DEC_HWI. The function is

called by a thread at the entry or exit depending on whether the

thread reads or writes compressed voice packets , respectively.

PRD_SWI 9 Periodic Interrupt. This thread is configured to run every 1 ms.

COM_SWI n/a COM Port Polling Service Routine. This thread is presently

implemented as function, i.e. it is not a true thread. It is called

within the SYS_PRD thread. It is runs once every 1 ms.

ENC_SWI 10 Encoder. This thread calls the vocoder analysis functions

(encoder). It converts linear voice data to compressed voice data.

It typically completes execution within 7.5 ms (includes the

execution time for higher priority threads). It is triggered once

every 20 ms (normal timing).

1 2 ... 42 43 44 45 46 47 48 49 50 51 52 ... 108 109

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