Sd I/O; Sd I/O Interrupts; Table 20-23 Sd Status Register - Motorola DragonBall MC9328MX1 Reference Manual

Multimedia Card/Secure Digital Host Controller Module (MMC/SD)
Bit Bit Name
511:510 DAT_BUS_WIDTH
509 SECURED_MODE
508:496 Reserved
495:480 SD_CARD_TYPE
479:448 SIZE_OF_
PROTECTED_AREA
447:312 Reserved
311:0 Reserved for manufacturer

20.7.7 SD I/O

I/O access differs from memory access because the I/O registers can be written and read individually and
directly without a File Allocation Table (FAT) file structure or the concept of blocks (although block
access is supported). These registers allow access to the I/O data, control of the I/O functions, report on
status of data, and transfer I/O data to/from the MMC/SD module.
Each SD I/O card can have between 1 and 7 functions plus one memory function built into it. A function is
a self-contained I/O device. These functions can be identical or completely different from each other. All
I/O functions are organized as a collection of registers, and there are a maximum of 131,072 registers
possible for each I/O function.

20.7.7.1 SD I/O Interrupts

To allow the SD I/O card to interrupt the MMC/SD module, and interrupt function is available on a pin on
the SD interface. Pin 8, used as SD_DAT [1] when operating in the 4-bit SD mode, signals the card's
interrupt to the MMC/SD module. The use of the interrupt is optional for each card or function within a
card. The SD I/O interrupt is level sensitive, which means that the interrupt line must be held active (low)
until it is either recognized and acted upon by the MMC/SD module or deasserted due to the end of the
interrupt period. After the MMC/SD module has serviced the interrupt, the interrupt status bit is cleared via
an I/O write to the appropriate bit in the SD I/O card internal registers. The interrupt output of all SD I/O
cards is active low and the MMC/SD module provides pull-up resistors on all data lines (SD_DAT [3:0]).
The MMC/SD module samples the level of Pin 8 (SD_DAT [1]/IRQ) into the interrupt detector only
during the interrupt period. At all other times, the MMC/SD module ignores this value.
20-52
Table 20-23. SD Status Register
Type Settings
S R 00 = 1-bit width
01 = reserved
10 = 4-bit width
11 = reserved
S R 0 = Not in secured
mode
1 = In secured mode
S R 0 = SD Memory
Cards
1 = SD I/O Cards
S R See Description
MC9328MX1 Reference Manual
Description
Shows the currently defined data
bus width that is defined by
(ACMD6,
SET_BUS_WIDTH
1-bit width is default)
Card is in secured mode of
operation
Selects between SD Memory and
SD I/O cards.
Size of protected area (in units
defined by SET_BLOCKLEN
CMD16)
Clear
Condition
A
A
A
A
,
MOTOROLA