BT8110 View Datasheet(PDF) - Unspecified

Part Name

Description

View to exact match

BT8110

High-Capacity ADPCM Processor

Unspecified 

3

3.0 Registers

NOTE: For a summary of all registers refer to the Register Summary section at the

end of this chapter.

3.1 0x00–0x3F—Per-Channel Control Registers (per_chan_ctrl)

Per-channel Control Registers can be used by the microprocessor to set the code selection, transparency,

algorithm reset, and PCM coding type on a per-channel basis. This capability allows each channel configuration

to be set without having to generate input control signals in hardware for each channel. Per-channel control

registers are write-only. Any attempt by the microprocessor to read these registers will result in erroneous data.

Four code select bits (CODE[3:0]) select up to 14 different codes from ROM. This allows a single

Bt8110/8110B to realize all of the ADPCM coding algorithms contained in the ANSI standards and ITU-T

recommendations for ADPCM coding. Maximum flexibility can be achieved with a single device for all

ADPCM applications. Specific code assignments depend on the coding of the ROM that is a part of the

Bt8110/8110B set. The standard codes that can be provided are the 32 kbit/s code in ITU-T Recommendation

G.726 and ANSI Standard T1.303-1989, the 24 and 40 kbit/s codes given in ANSI Standard T1.303-1989, and

all of the embedded codes in ANSI Standard T1.310-1991 and ITU-T Recommendation G.727. Only six of the

codes can be embedded codes.

6

EN_ALAW

EN_ALAW

EN_RST

EN_TRPT

CODE[3:0]

5

EN_RST

4

EN_TRPT

3

CODE[3]

2

CODE[2]

1

CODE[1]

0

CODE[0]

Enable A-Law Coding—Sets the encoder PCM input and decoder PCM output coding law to

A-law. If this control is not set, the coding law is µ-law.

Enable Reset—Causes the algorithm reset input to be continuously applied as long as the bit is

set. This function is according to ANSI Standard T1.303-1989 and is useful for Digital Circuit

Multiplexing Equipment (DCME) functions.

Enable Transparent Operation—Uses the Bt8110/8110B to transfer the 8-bit input to the

output without any modifications for both encoder and decoder channels. The delay of the

Bt8110/8110B is the same for transparent operation as it is for coded (normal) operation.

Code Select—Selects among the 14 codes contained in the ROM lookup table. For the Bt8110

this table is provided by Conexant in a 128 K ROM, upon request. Each code block is 1024

bytes and can be reorganized in the ROM by the user, except for blocks 6 and 7 which are

reserved.

100060C

Conexant

3-1

Share Link: