Samsung S3C2451X User Manual page 471

S3C2451X RISC MICROPROCESSOR
SEQUENCE
This section defines basic sequence flow chart divided into several sub sequences. "Wait for interrupts" is used in
the flow chart. This means the Host Driver waits until specified interrupts are asserted. If already asserted, then
fall through that step in the flow chart. Timeout checking shall be always required to detect no interrupt generated
but this is not described in the flow chart.
SD CARD DETECTION SEQUENCE
The flow chart for detecting a SD card is shown in Figure 21-2. Each step is executed as follows:
(1) To enable interrupt for card detection, write 1 to the following bits:
Card Insertion Status Enable(ENSTACARDNS) in the Normal Interrupt Status Enable register
Card Insertion Signal Enable(ENSIGCARDNS) in the Normal Interrupt Signal Enable register
Card Removal Status Enable(ENSTACARDREM) in the Normal Interrupt Status Enable register
Card Removal Signal Enable(ENSIGCARDREM) in the Normal Interrupt Signal Enable register
(2) When the Host Driver detects the card insertion or removal, clear its interrupt statuses. If Card Insertion
interrupt(STACARDINS) is generated, write 1 to Card Insertion in the Normal Interrupt Status register. If Card
Removal interrupt(STACARDREM) is generated, write 1 to Card Removal in the Normal Interrupt Status register.
(3) Check Card Inserted in the Present State register. In the case where Card Inserted(INSCARD) is 1, the Host
Driver can supply the power and the clock to the SD card. In the case where Card Inserted is 0, the other
executing processes of the Host Driver shall be immediately closed.
Figure 21-2SD Card Detect Sequence
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
HSMMC CONTROLLER
21-3