Samsung S5PC100, Руководство пользователя

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S5PC100 USER’S MANUAL (REV1.0) SD/MMC CONTROLLER
8.12-37
PRNSTS Bit Description Reset Value
Software Reset register does not affect this bit. If a card is removed
while its power is on and its clock is oscillating, the Host Controller
clears SD Bus Power in the Power Control register and SD Clock
Enable in the Clock Control register.
If this bit is changed from 1 to 0, the Host Controller immediately
stops driving CMD and DAT[3:0] (tri-state). In addition, the Host
Driver must clear the Host Controller by the Software Reset For All in
Software Reset register. The card detect is active regardless of the
SD Bus Power.
1 = Card Inserted
0 = Reset or Debouncing or No Card
Reserved
[15:12] Reserved
BUFRDRDY [11]
Buffer Read Enable (ROC)
This status is used for non-DMA read transfers. The Host Controller
implements multiple buffers to transfer data efficiently. This read only
flag indicates that valid data exists in the host side buffer status. If this
bit is 1, readable data exists in the buffer. A change of this bit from 1
to 0 occurs if all the block data is read from the buffer. A change of
this bit from 0 to 1 occurs if block data is ready in the buffer and
generates the Buffer Read Ready interrupt.
1 = Enables Read
0 = Disables Read
0
BUFWTRDY [10] Buffer Write Enable (ROC)
This status is used for non-DMA write transfers. The Host Controller
implements multiple buffers to transfer data efficiently. This read only
flag indicates if space is available for write data. If this bit is 1, data is
written to the buffer. A change of this bit from 1 to 0 occurs if all the
block data is written to the buffer. A change of this bit from 0 to 1
occurs if top of block data is written to the buffer and generates the
Buffer Write Ready interrupt.
1 = Write enable
0 = Write disable
0
RDTRANACT [9] Read Transfer Active (ROC)
This status is used to detect completion of a read transfer.
This bit is set to 1 for either of the following conditions:
(1) After the end bit of the read command.
(2) If writing a 1 to Continue Request in the Block Gap Control
register to restart a read transfer.
This bit is cleared to 0 for either of the following conditions:
(1) If the last data block as specified by block length is transferred to
the System.
(2) If all valid data blocks have been transferred to the System and no
current block transfers are being sent as a result of the Stop At Block
Gap Request being set to 1. A Transfer Complete interrupt is
generated if this bit changes to 0.
1 = Transferring data
0 = No valid data
0