MAS 35x9F
DATA SHEET
3.3.4.1. Application Selection and
Application Running
3.3.4.2. Application Specific Control
The configuration of the MPEG Layer 2/3, AAC decod-
ing and the G.729 codec firmware is done via the con-
trol memory cells described in Table 3–9. The changes
applied to any of the control memory cells have to be
validated by setting bit[0] of memory cell Main I/O Con-
trol. This bit will be reset automatically after the
changes have been taken over by the DSP.
The AppSelect cell is a global user interface configura-
tion cell, which has to be written in order to start a spe-
cific application.
The AppRunning cell is a global user interface status
cell, which indicates, which application loop is actually
running.
The status memory cells in Table 3–11 are used to
read the decoder status and to get additional MPEG
bitstream information.
1. Write “0” to AppSelect
2. Check AppRunning for “0”
3. Write value to AppSelect according to Table 3–8
(determines start time of Application program)
Note: DSP memory cells not given in Table 3–8 or
Table 3–9 must not be written.
4. Apply necessary/wanted control settings
(D0:346..357)
Table 3–8: D0 control memory cells: mode selection
Memory
Address
(hex)
Function
Name
D0:34b
Application Selection
All AppSelect
AppSelect is used for selecting an application. This is done by setting the
appropriate bit to one. It is principally allowed to set more than one bit to one,
e.g. setting AppSelect to 1C
will select all MPEG audio decoders. The
hex
auto-detection feature will automatically detect the Layer 2, Layer 3, or AAC
data. Setting bit[0] or bit[1] will make the DSP loop in the OS loop or the Top
Level loop respectively.
To add/remove MPEG layers while running in MPEG decoding mode (e.g.
change from Layer 2, Layer 3 (0C ) to Layer 2, Layer 3, AAC (1C )), the
hex
hex
application selection has to be reset to 00
before writing the new value.
hex
bit[5]
bit[4]
bit[3]
bit[2]
bit[1]
bit[0]
G.729 Codec
MPEG AAC Decoder
MPEG Layer 3 Decoder
MPEG Layer 2 Decoder
Top Level
Operating System
D0:34c
Application Running
All AppRunning
The AppRunning cell is a global user interface status cell, that indicates which
application loop is actually running. Prior to writing any of the configuration
registers or memory cells (except AppSelect), it has to be checked whether
the appropriate bit(s) in the AppRunning cell is set.
bit[5]
bit[4]
bit[3]
bit[2]
bit[1]
bit[0]
G.729 Codec
MPEG AAC Decoder
MPEG Layer 3 Decoder
MPEG Layer 2 Decoder
Top Level
Operating System
32
June 30, 2004; 6251-505-1DS
Micronas
MICRONAS [ MICRONAS ]
