PRELIMINARY DATA SHEET
MICRONAS
INTERMETALL
CAP 3540B,
CAP 3541B
Car Audio Processor
Hardware
MICRONAS
Edition May 22, 1997
6251-434-1PD
CAP 3540B, CAP 3541B
Contents
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2
Section
1.
1.1.
2.
2.1.
2.1.1.
2.1.2.
2.1.3.
2.1.4.
2.2.
2.2.1.
2.2.2.
2.2.3.
2.2.4.
2.2.5.
2.2.5.1.
2.2.6.
2.2.6.1.
2.2.6.2.
2.2.7.
2.3.
2.3.1.
2.3.2.
2.3.3.
2.4.
2.5.
2.5.1.
2.6.
3.
3.1.
3.2.
3.3.
3.4.
3.5.
3.5.1.
3.5.2.
3.5.3.
3.5.4.
4.
5.
6.
7.
8.
9.
Title
Introduction
Features
Functional Description
Architecture
DSP Block
Digital Part
Analog Part
Operating Modes
Analog Input Systems
Buffers ABUF
Stereo Mixer AMIX
Multiplexers AMUX
A/D-Converters ADC
Digital Signal Processing Block
Digital Filter Sections
Digital Mixing Systems
Pilot Demodulator PILMX
ARI Mixer ARIMIX
FM Noise Canceller (ASU)
Analog Output Systems
D/A Converters DAC
Lowpass-Filters ALPF
Volume Control AVOL
Programmable Digital Audio Interface (PDAI)
The IM-Bus Interface of the CAP 3540B
Description of the IM-Bus
Clock Generation
Specifications
Outline Dimensions
Pin Connections and Short Descriptions
Pin Descriptions
Pin Configuration
Electrical Characteristics
Absolute Maximum Ratings
Recommended Operating Conditions
Recommended Crystal Characteristics
Characteristics
Starting the Processor
Synthesizer
Application Notes
Typical Application Circuit
Index
Data Sheet History
PRELIMINARY DATA SHEET
MICRONAS INTERMETALL
PRELIMINARY DATA SHEET
CAP 3540B, CAP 3541B
1.1. Features
– High-quality audio A/D converters with input selectors
for several analog audio sources
– D/A converters with 8-fold oversampling filters
– Baseband audio processing (bass/treble, loudness,
volume, balance and fader control)
– Stereo decoder
– Noise concealment for weak FM signals, including Au-
tomatic Separation Control, Hi-Blend and Volume-
Blend function
– Ignition noise canceller: removes peak noise from the
audio signal and interpolates the disturbed audio sam-
ples
– RDS processing: demodulation of the Radio Data Sys-
tem signal; RDS clock and data are available via hard-
ware pins and software control bus
– Deemphasis and 19 kHz Pilot tone filter for FM
– Detection of field strength, multipath and peak noise
levels
– Music search for tape player
– Freely programmable Digital Audio Interface for CD/
DCC and coprocessor applications
(only with CAP 3540B)
– Synthesizer with 3 current sources for fast FM/AM tun-
ing
A more detailed overview about the integrated DSP-fea-
tures is given in the additional Application Note Software
CAP 3540B.
Car Audio Processor
1. Introduction
The CAP 3540B Car Audio Processor is a new CMOS
processor and represents the one-chip solution for a
highly integrated AM/FM radio concept.
The CAP 3540B is designed for car radio concepts and
can also be used for home stereo receivers, as well as
for PC radio cards.
The CAP 3541B is especially designed for applications
without digital audio sources. Digital audio input is not
supported in the CAP 3541B. All other features are com-
patible to the CAP 3540B. In the following description,
only the CAP 3540B is mentioned.
The typical application consists of the following compo-
nents:
– Car Audio Processor CAP 3540B
– conventional FM tuner and FM-IF stage
– conventional AM tuner and AM-IF stage
– microcontroller
– analog and digital (only with CAP 3540B) audio
sources
– power amplifiers
MICRONAS INTERMETALL
3
CAP 3540B, CAP 3541B
2. Functional Description
2.1. Architecture
The architecture of the CAP 3540B processor com-
prises three main function blocks:
2.1.1. DSP Block
The DSP block consists of a “General-Purpose16-Bit
Digital Signal Processor” which handles 24 million in-
structions per second. The data word length is 16 bits
and the hardware multiplier operates with an initial word
length of 16@10 with a 20-bit result. The memory covers
256@16+256@10 bit RAM and 2 k instruction ROM.
2.1.2. Digital Part
A main portion consists of hardwired digital filters, such
as decimation filters for the A/D converters and interpo-
lation filters for D/A converters. The modulators for ARI/
RDS and pilot tone, as well as the complete circuitry for
the ignition noise canceller are realized digitally. The log-
ical conclusion for a higher integration is the incorpora-
tion of the synthesizer for AM and FM tuning into this
hardware block. Naturally, the customary serial inter-
faces for digital audio signals are also included.
2.1.3. Analog Part
In the analog part various input switches, A/D converters
and D/A converters are combined. Five A/D converters
handle the conversion of analog signals into digital sig-
nals. Two of these are specially designed for high quali-
ty, one in particular for the conversion of an independent
signal path for ARI/RDS signals and the remaining two
to be used for the evaluation of analog signals of a lower
quality standard (information on field strength and infor-
mation from potentiometers). Two D/A converters, each
equipped with an eightfold oversampling filter, generate
analog output signals. These two outputs can be split up
and distributed into four output stages via four indepen-
dently adjustable volume control switches.
PRELIMINARY DATA SHEET
4
MICRONAS INTERMETALL
MICRONAS INTERMETALL
5
PRELIMINARY DATA SHEET
Fig. 2–1:
CAP 3540B block diagram
SCLKI
L+R
Programmable
Digital Audio
Interface
(not in CAP 3541B)
SCLKO
SDOUT
SDIN2
WSO
SDIN1
WSI
ERR
A/D 0
L–R
MPX0
MPX
Decoder
L–R
AMR
AML
FM-Noise
Reduction
DSP Core
Stereo Matrix
Tone Control
Pilot Filter
Loudness
Deemphasis
Noise Reduction
Volume
Balance
Input
Select
A/D 1
L+R
Over-
sampled
D/A
DSP
Output
Buffer
Analog
Volume
LF
LR
FM-Noise
Detection
Analog
Volume
TAPER
TAPEL
AUXR
AUXL
Pilot
Mixer
DSP
Input
Buffer
A/D 2
ARI/RDS
Mixer
RDS Demodulation
POT1/MPX1
POT2
POT3
POT4
POT5/AVC
FMLEVEL
MPLEVEL
AMLEVEL
Input
Select
Multipath Detection
FM/AM-Level Detection
Peak Noise Detection
A/D3
Stereo PLL Filter
Stereo Detection
Stereo Soft Blend
Hi-Blend
Volume Blend
Blank Search
Beep Generator
CAP 3540B, CAP 3541B
Over-
sampled
D/A
Analog
Volume
RF
RR
Analog
Volume
Input
Select
A/D 4
Synthesizer
Auxiliary
Digital Inputs
Auxiliary
Digital Outputs
IM-Bus
Interface
Clock
QX1
FMIN
AMIN
AMTUNOUT
FM TUNOUT
TI1
TI2
TI3
TO1 TO2 TO3
IMDATA
IMIDENT
QX2/ECLK
IMCLOCK
CLKOUT
模拟与混合信号
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