SAF7849HL/M295,557 NXP Semiconductors, SAF7849HL/M295,557 Datasheet - Page 36

• Manufacturer Part Number: SAF7849HL/M295,557
• Description: IC AUD DECODER 144LQFP
• Manufacturer: NXP Semiconductors
• Type: Audio Decoderr

Specifications of SAF7849HL/M295,557

• Applications: Audio CD
• Voltage - Supply, Analog: 3 V ~ 3.6 V
• Voltage - Supply, Digital: 1.8V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 144-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 935287932557

NXP Semiconductors
SAF784X_2
Product data sheet
6.5.6.3 CD-text interface
Table 9.
After finishing a subcode read, the microcontroller must release the interface to allow the
decoder to capture new subcode information. This is done by issuing a read to register
SubcodeQReadend.
The availability of a new subcode frame will also trigger an interrupt if InterruptEnable2 bit
SUBCODEREADYENABLE is set.
The channel decoder contains an internal buffer which stores CD-text information (format
4, available in the lead-in area). The buffer can hold one CD-text pack for readback, while
at the same time, it receives the next pack.
The operation of the CD-text readback interface is controlled via register CDTEXTControl.
Bit FREEZEEN determines whether or not the internal buffer is frozen during readback
(such that the next pack cannot overwrite the current one before the microprocessor has
finished reading). Bit CRCFAILEN determines whether or not packs with a failed CRC
check are made available for readback.
This subcode can be retrieved by the microcontroller, by accessing the registers
CDTEXTStatus, CDTEXTData and CDTEXTReadEnd.
To start retrieving the CD-text pack, the microcontroller must first read the register
CDTEXTStatus. This register contains various status bits that indicate the status of the
CD-text pack that may be read. When, after reading the register CDTEXTStatus, the
TEXTREADY bit is found HIGH, the CDTEXT interface will be blocked (indicated by
TEXTBUSY going HIGH) so that no new subcode will overwrite the current one; at least if
CDTEXTControl bit FREEZEEN is turned on. TextCRCOK indicates if the current CD-text
pack was indicated correctly, or not, by a hardware CRC check.
After reading CDTEXTStatus with TEXTREADY = '1', the microcontroller may retrieve as
many CD-text bytes as required (16 maximum) by issuing subsequent reads to register
CDTEXTData.
After finishing CD-text read, the microcontroller must release the interface to allow the
decoder to capture new CD-text information. This is done by issuing a read to register
CDTEXTReadEnd.
Remark: If CDTEXTControl bit FREEZEEN is disabled, the interface is not held during
readback, which means it is possible that the current CD-text pack is overwritten by the
next one before all bytes of the current pack are read out. Such an event will be indicated
by setting CDTEXTReadEnd bit BUFFEROVERFLOW HIGH, so that it can be noticed by
software at the end of the pack read.
The availability of a new CD-text pack will also trigger an interrupt if InterruptEnable1 bit
CDTEXTREADYENABLE) is set.
Address/Byte
8
9
10
Q-channel subcode frame content
Name
ABS MIN
ABS SEC
ABS FRAME
One chip CD audio device with integrated MP3/WMA decoder
Rev. 02 — 9 May 2008
…continued
Comments
Mod100
Mod 60
Mod 75
absolute time
SAF784x
© NXP B.V. 2008. All rights reserved.
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