peb20560 Infineon Technologies Corporation, peb20560 Datasheet - Page 157

• Manufacturer Part Number: peb20560
• Description: Dsp Oriented Pbx Controller Doc
• Manufacturer: Infineon Technologies Corporation

this method, DSP SW access to the circular buffer should not be aware the value of
Current Block (CB) signal, or the correct circular buffer blocks to which the DSP should
access during the current frame:
• For any DSP access to the circular buffer, the most significant byte of the address
• The decoding of the least significant byte of the address is different in each mode, and
Circular-buffer write/read address in modes 0, 1 and 2
In modes 0, 1, 2 the circular buffer is divided into 4 IN blocks and 4 OUT blocks–32 words
each. This is shown in Table 2-22 and Figure 2-42.
When working in one of these modes, decoding of circular buffer write address is
described as follows:
bit
bit
Index4…0
Stream 0/1
Bit 7, Bit 5
When working in modes 0-2, decoding of circular buffer read address is as follows:
bit
bit
Index4…0
Semiconductor Group
should be F0
during write operation or read operation to/from the circular buffer.
15
7
15
7
‘1’
‘1’
‘1’
‘0’
This field defines the index of the specific word in a 32 words
circular-buffer block.
0 = stream 0
1 = stream 1
This field defines if the access is to a block of
OUT-stream 0 (DSP-OUT0-0, DSP-OUT0-1) or of
OUT-stream 1 (DSP-OUT1-0 or DSP-OUT1-1).
These should always be ‘1’ during a write operation.
This field defines the index of the specific word in a 32 words
circular-buffer block.
H
.
14
6
14
6
stream
stream
0/1
0/1
‘1’
‘1’
13
5
13
5
‘1’
‘1’
‘1’
‘0’
12
4
12
4
indeX
indeX
2-111
(4)
(4)
‘1’
‘1’
11
3
11
3
index
index
(3)
(3)
‘0’
‘0’
Functional Block Description
10
2
10
2
index
index
(2)
(2)
‘0’
‘0’
9
1
9
1
index
index
(1)
(1)
‘0’
‘0’
PEB 20560
8
0
8
0
index
index
2003-08
(0)
(0)
‘0’
‘0’