MMC/SD Host Controller
7-141
MPU Public Peripherals
Card Enter Busy State (Card_Busy)
MMC/SD mode only.
The core automatically sets this bit (2) when the addressed card asserts the
DAT line to a low level during a programming phase (write operation) to a MMC
or SD memory card. For the MMC card only, the user can optionally use this
interrupt to deselect the card (which continues to program) and select another
card.
In SPI or SYSTEST modes, this bit has no meaning and always reads as 0.
-
0: No action
-
1: Data line asserted low/card busy
Value after reset is low.
End of Command (End_of_Cmd)
MMC/SD mode only.
The core automatically sets this bit (0) at the end of a successful command/
response sequence or at the end of a command without response. This bit is
not set in case of a card status error.
In SPI or SYSTEST modes, this bit has no meaning and always reads as 0.
-
0: No action
-
1: End of command/response sequence
Value after reset is low.
When a CMD12 command is transferred after a multiple block read, the
End_of_Cmd bit [0] is not set. Alternatively, the Card_Busy bit [2] is set. After
this, the EOF_Busy bit [4] cannot be set. Avoid this condition with software by
using the following sequence:
1) Mask the busy interrupt before the CMD12 command is sent, because it
is possible that the unexpected busy interrupt to the MPU is generated.
2) Clear the Card_Busy [2] after the response for CMD12 is returned,
because it is possible that this flag is set.
3) Enable the busy interrupt if it is to be used (write 0xFFFF to the MMC_IE
register).