S5L9274 Ver la hoja de datos (PDF) - Samsung

Número de pieza

componentes Descripción

Fabricante

S5L9274

DECODER FOR CD-MP3/CD-ROM

Samsung 

DECODER FOR CD-MP3/CD-ROM

S5L9274

MICOM PROGRAMMING GUIDELINE

Transferring Input Bitstream to S5L9274

Micom is allowed to initiate the transfer when the Input Buffer is in LOW state which is by the "Input Buffer State"

Interrupt (See section skip function) from CD-MP3 IC.

Burst Transfer with the number of sectors being transferred.

 Verify the Input Buffer is in LOW state. The register H_IB_STATE tells Input Buffer (Empty, Low, or High).

When there is any change in the H_IB_STATE, "Input Buffer " Interrupt arises, and External MCU can read

the H_IB_STATE to know the Input State. When Input Buffer is in lower than the "Input Buffer Low

Threshold" we say is in LOW state. Input Buffer Low Threshold is determined by the value of the register

_IB_WR_OFFSET. It has the following relationship.

Low Threshold = (Input Buffer Size in number of words) - (H_IB_WR_OFFSET)*1024

 Micom decides the start sector address from which the CD-ROM sectors are transferred S5L9274.

 Write number of sectors being transferred into H_FRAME_NO register.

 Micom initiate to transfer CD-ROM sectors from CDP subsystem to S5L9274 starting the address (MSF)

which is several sectors ahead the start sector address.

 Micom gets sector address information (MSF) from CDP subsystem while CDP transfers CD-ROM sectors to

S5L9274.

 Micom checks continuously if the MSF received from CDP subsystem is reached at the MSF from which

Micom wants to put the corresponding sector in S5L9274.

 If the MSF received from CDP subsystem is reached at (the start MSF - 1), Micom "0x91" to H_OPSR_W in

S5L9274 to allow for S5L9274 to start decode sectors when sector boundary is reached.

 When "Dump-End" interrupt encountered during sector transfer, read the H_DUMP_CNT and check if the

content of the H_DUMP_CNT is equal to the content of _FRAME_NO. If they are equal, it indicates all

sectors have been transferred successfully if they are not, it indicates that Input Buffer High condition were

met in the middle of transfer and the remaining transfer has been discarded after that condition. If that n has

occurred, Micom should transfer again from the sector which was cancelled. new start sector address can be

calculated with the previous start sector address and content of the H_DUMP_CNT register.

* S5L9274 set the "Dump-End" interrupt when the content of the H_DUMP_CNT is equal to content of

H_FRAME_NO and also when Input Buffer High condition were met during transfer.

19

Share Link: