MSP 34x2G
PRELIMINARY DATA SHEET
6.5.6. Identification Mode for A2 Stereo Systems
6.6. Manual/Compatibility Mode:
Description of DSP Read Registers
Identification Mode
00 15hex
L
All readable registers are 16-bit wide. Transmissions
via I2C bus have to take place in 16-bit words. Some of
the defined 16-bit words are divided into low and high
byte, thus holding two different control entities.
Standard B/G
(German Stereo)
0000 0000
RESET
00hex
Standard M
(Korean Stereo)
0000 0001
0011 1111
01hex
3Fhex
These registers are not writable.
Reset of Ident-Filter
6.6.1. Stereo Detection Register
for A2 Stereo Systems
To shorten the response time of the identification algo-
rithm after a program change between two FM-Stereo
capable programs, the reset of the ident-filter can be
applied.
Stereo Detection
Register
00 18hex
H
Stereo Mode
Reading
(two’s complement)
Sequence:
1. Program change
MONO
near zero
2. Reset ident-filter
STEREO
positive value (ideal
reception: 7Fhex
)
3. Set identification mode back to standard B/G or M
4. Wait approx. 500 ms
BILINGUAL
negative value (ideal
reception: 80hex)
5. Read stereo detection register
Note: This register is initialized during STANDARD
SELECTION and is automatically updated when Auto-
matic Sound Select (MODUS[0]=1) is on.
Note: It is no longer necessary to read out and evalu-
ate the A2 identification level. All evaluation is per-
formed in the MSP and indicated in the STATUS regis-
ter.
6.5.7. FM DC Notch
6.6.2. DC Level Register
The DC compensation filter (FM DC Notch) for FM
input can be switched off. This is used to speed up the
automatic search function (see Section 6.4.7.). In nor-
mal FM-mode, the FM DC Notch should be switched
on.
DC Level Readout
FM1 (MSP-Ch2)
00 1Bhex
00 1Chex
H+L
H+L
DC Level Readout
FM2 (MSP-Ch1)
FM DC Notch
00 17hex
L
DC Level
[8000hex ... 7FFFhex]
values are 16 bit two’s
complement
ON
0000 0000
Reset
00hex
OFF
0011 1111
3Fhex
The DC level register measures the DC component of
the incoming FM signals (FM1 and FM2). This can be
used for seek functions in satellite receivers and for IF
FM frequencies fine tuning. A too low demodulation
frequency (DCO) results in a positive DC-level and
vice versa. For further processing, the DC content of
the demodulated FM signals is suppressed. The time
constant τ, defining the transition time of the DC Level
Register, is approximately 28 ms.
98
Micronas
MICRONAS [ MICRONAS ]
