Audio Interface Module (AIM)
MCF5253 Reference Manual, Rev. 1
17-26
Freescale Semiconductor
17.6.3.1
Free Running Counter Synchronization
There is a synchronization issue on start-up between the MCF5253 and some channel encoders. On
start-up, the RCK clock is kept silent. At a certain point in time, the CDR60
1
will start clocking the RCK,
and then it will require that the first symbol transmitted from the MCF5253 to the CDR60 is a sync symbol.
If this is not the case, the CDR60 fails to synchronize.
To solve the synchronization issue, the counter that determines the sync position can be preset using the
register CdTextControl (
).
17.6.3.2
Controlling the SFSY Sync Position
When RCK is not clocking, it is possible to control the subcode byte number that will be sent out next by
the CD-Subcode interface by writing CdTextControl with PresetEn set to 1.
•
When 0 is written to presetCount, the next byte sent out is a CD-Subcode sync byte. (SFSY low).
•
When a value (97–i) is written to presetCount, i non-sync bytes are transmitted, followed by a sync
byte.
•
After writing to CdTextControl with PresetEn set to 1, next bit out is always the first bit of a new
byte.
•
Writing CdTextControl with PresetEn set to 1, while RCK is running, will result in unpredictable,
undefined operation.
17.6.4
Inserting CD User Channel Data Into IEC958 Transmit Data
Source selection of data transmitted into the User Channel of the IEC958 transmitter is selected by bits
(1,0) of register EBUConfig.
•
When selected the source is the IEC958 receiver, every user channel data byte received into the
input of the IEC958 user channel, is inserted into the outgoing stream at approximately. the same
time it was found in the incoming stream.
•
When the selected source is CD-Subcode, every data byte transmitted over the CD-Subcode output
is also inserted into the IEC958 output stream. The most significant bit of every byte is transmitted
as a “1”. All sync symbols are transmitted as all-0.
•
In case the RCK clock is not present, it is still possible to use the CD-Subcode interface to assemble
the outgoing IEC958 User channel data. In this case, bit UChanTxTim in register
CDTEXTCONTROL must be set ‘1’ (
). It will cause the timing to the CD-Subcode
registers to be controlled by the IEC958 transmitter. One symbol (data or sync) will be transmitted
into the IEC958 output every 12 User Channel data bits.
17.7
Processor Interface Overview
The interface between the processor and the Audio Modules is given in this section.
, shows
a simplified picture of the interface between the audio modules and the processor core.
1.
CDR60 is the informal name for Philips CD-R channel encoder
Summary of Contents for MCF5253
Page 1: ...Document Number MCF5253RM Rev 1 08 2008 MCF5253 Reference Manual...
Page 26: ...MCF5253 Reference Manual Rev 1 xxvi Freescale Semiconductor...
Page 32: ...MCF5253 Reference Manual Rev 1 xxxii Freescale Semiconductor...
Page 46: ...MCF5253 Introduction MCF5253 Reference Manual Rev 1 1 14 Freescale Semiconductor...
Page 62: ...Signal Description MCF5253 Reference Manual Rev 1 2 16 Freescale Semiconductor...
Page 98: ...Instruction Cache MCF5253 Reference Manual Rev 1 5 10 Freescale Semiconductor...
Page 104: ...Static RAM SRAM MCF5253 Reference Manual Rev 1 6 6 Freescale Semiconductor...
Page 128: ...Synchronous DRAM Controller Module MCF5253 Reference Manual Rev 1 7 24 Freescale Semiconductor...
Page 144: ...Bus Operation MCF5253 Reference Manual Rev 1 8 16 Freescale Semiconductor...
Page 176: ...System Integration Module SIM MCF5253 Reference Manual Rev 1 9 32 Freescale Semiconductor...
Page 198: ...Analog to Digital Converter ADC MCF5253 Reference Manual Rev 1 12 6 Freescale Semiconductor...
Page 246: ...DMA Controller MCF5253 Reference Manual Rev 1 14 18 Freescale Semiconductor...
Page 282: ...UART Modules MCF5253 Reference Manual Rev 1 15 36 Freescale Semiconductor...
Page 344: ...Audio Interface Module AIM MCF5253 Reference Manual Rev 1 17 46 Freescale Semiconductor...
Page 362: ...I2 C Modules MCF5253 Reference Manual Rev 1 18 18 Freescale Semiconductor...
Page 370: ...Boot ROM MCF5253 Reference Manual Rev 1 19 8 Freescale Semiconductor...
