MT92220BG Zarlink Semiconductor, MT92220BG Datasheet - Page 138

• Manufacturer Part Number: MT92220BG
• Description: Description = 1023 Channel Voice Over IP/AAL2 Processor ;; Package Type = Epbga ;; No. Of Pins = 608
• Manufacturer: Zarlink Semiconductor

138
TX Circular Buffer
Base / Size
Indication
N
IL
OL
C
TX Circular Buffer
Base [20:8] /
SOP[14:5]:
Add
HBC
Write Offset
Circular Buffer
Read Pointer
Buf Size
HT
Field
This field indicates the base address and size of the circular buffer in which values
received from the TDM bus must be written. The size range is 256 bytes to 1K bytes.
Nibble mode. ‘0’ = ADPCM nibbles in high bits; ‘1’ = ADPCM nibbles in low bits.
In law. Determines the PCM law of samples received from the TDM bus. ‘0’ = u-law; ‘1’ =
A-law.
Out law. Determines the PCM law of samples written to the TX Circular Buffer. ‘0’ = u-law;
‘1’ = A-law.
Compression type.
“000” = PCM,
“001” = ADPCM 40 kbps,
“010” = ADPCM 32 kbps,
“011” = ADPCM 24 kbps,
“100” = ADPCM 16 kbps;
“101” = ADPCM only autodetect (Associated Stream bit is cleared);
“110” = ADPCM & PCM autodetect (Associated Stream bit is set);
“111” = reserved.
this field represent the start of packet address of the packet that is currently being
received on the HDLC stream. The SOP part of this field should be written to zero by
software upon initialization of the HDLC stream.
HDLC Address of the current packet. This field should be initialized to zero by software
upon initialization of stream.
Header byte count. This field should be initialized to zero by software upon initialization of
stream.
This field indicates where the next received byte will be written in the TX Circular Buffer.
This offset is calculated using the SOP as its base. This field should be initialized to zero
by software upon initialization of stream.
This field is updated by the TX assembly block when packets are sent out. This field
should be initialized to zero by software upon initialization of stream.
Circular Buffer Size.
“000” = 256 bytes;
“001” = 512 bytes;
“010” = 1K bytes;
“011” = 2K bytes;
“100” = 4K bytes;
“101” = 8K bytes;
“110” = 16K bytes;
“111” = 32K bytes.
HDLC Type. ‘0’ = bit wise packet framing and escape code; ‘1’ = byte wise packet framing
and escape code.
Base address of the TX Circular Buffer used for the HDLC stream. The lower order bits of
Table 57 - Fields and Description
Zarlink Semiconductor Inc.
Description