mt90502ag2 Zarlink Semiconductor, mt90502ag2 Datasheet - Page 96

• Manufacturer Part Number: mt90502ag2
• Description: Multi-channel Aal2 Sar
• Manufacturer: Zarlink Semiconductor

One byte from each silent noise buffer is read at the beginning of each frame and written into internal memory.
Therefore a silent/tone value for each active silent channel is primed for the entire frame. The MT90502 can use up
to 96 silent noise buffers. In addition, up to 32 null bytes can be used, augmenting the actual number of padding
possibilities to 128. At the start of each frame, the MT90502 reads the address, size, and current read pointer of
every silent noise buffer, and then reads the corresponding byte. It then updates the read pointer for the next frame
and writes it back.
32 null bytes are stored in two locations in internal Tone Data Buffer Memory. Both locations must have identical
copies.
Silent/Tone Buffer Control Memory structures are 8-bytes in size, located in internal memory at addresses 2600h to 26F8h.
Base Address of Tone/Silent Buffer Pair: Points to a 64-byte boundary at which this silent buffer pair begins.
Size of Tone/Silent Buffer Pair: Indicates the size of this silent buffer pair.
0000h = invalid (this pair is not used)., 0001h = 1byte (per pattern), FFFFh = 65535-bytes (per pattern). Because this controls the size of
2 buffers, a full-sized pair will occupy 128 K-bytes.
Tone/Silent buffer Read Pointer: Current Read Pointer to this silent buffer pair. This field must be set to 0 by software when initialised.
137Eh
1360h
26F0h
26F8h
2600h
2608h
Silent/Tone Buffer 60-61
Silent/Tone Buffer 62-63
Silent/Tone Buffer 0-1
Null-byte [30]
Null-byte [0]
Silent/Tone Buffer 2-3
+N-1
+0
b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Even Tone Buffer
Even Tone Buffer
Figure 59 - Null Bytes in Tone Data Buffer Memory
Figure 58 - Silent Tone Buffer Pair in TX SSRAM
Figure 57 - SSRAM Tone Buffer Control Memory
Null-byte [31]
Null-byte [1]
Reserved
Zarlink Semiconductor Inc.
MT90502
Odd Tone Buffer
Odd Tone Buffer
+0
+2
+4
+6
b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
96
13FEh
13E0h
Base Address of Tone/Silent Buffer Pair [20:6]
Tone/Silent buffer Read Pointer [16;0]
Size of Tone/Silent buffer Pair
Index given by Base Address of
Tone/Silent
SSRAM Tone Buffer Control
memory (see Figure 57 -SSRAM
Tone Buffer Control Memory).
Null-byte [30]
Null-byte [0]
Buffer
Pair
Null-byte [31]
Null-byte [1]
in
Data Sheet