Sd I/O Mode; Table 153. Erase Offset Field - ST STM32F101 series Reference Manual

Secure digital input/output interface (SDIO)
ERASE_TIMEOUT
---------
63
ERASE_OFFSET
This 2-bit field indicates T
meaningless if the ERASE_SIZE and ERASE_TIMEOUT fields are set to 0.
0h
1h
2h
3h
22.4.13

SD I/O mode

SD I/O interrupts
To allow the SD I/O card to interrupt the MultiMediaCard/SD module, an interrupt function is
available on a pin on the SD interface. Pin 8, used as SDIO_D1 when operating in the 4-bit
SD mode, signals the cards interrupt to the MultiMediaCard/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 MultiMediaCard/SD module or deasserted due to the end
of the interrupt period. After the MultiMediaCard/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's
internal registers. The interrupt output of all SD I/O cards is active low and the application
must provide pull-up resistors externally on all data lines (SDIO_D[3:0]). The
MultiMediaCard/SD module samples the level of pin 8 (SDIO_D/IRQ) into the interrupt
detector only during the interrupt period. At all other times, the MultiMediaCard/SD module
ignores this value.
The interrupt period is applicable for both memory and I/O operations. The definition of the
interrupt period for operations with single blocks is different from the definition for multiple-
block data transfers.
SD I/O suspend and resume
Within a multifunction SD I/O or a card with both I/O and memory functions, there are
multiple devices (I/O and memory) that share access to the MMC/SD bus. To share access
to the MMC/SD module among multiple devices, SD I/O and combo cards optionally
implement the concept of suspend/resume. When a card supports suspend/resume, the
MMC/SD module can temporarily halt a data transfer operation to one function or memory
(suspend) to free the bus for a higher-priority transfer to a different function or memory. After
this higher-priority transfer is complete, the original transfer is resumed (restarted) where it
left off. Support of suspend/resume is optional on a per-card basis. To perform the
587/1128
Table 152. Erase timeout field (continued)
---------
63 [sec]
and one of four values can be selected. This field is
OFFSET

Table 153. Erase offset field

ERASE_OFFSET
DocID13902 Rev 15
Value definition
Value definition
0 [sec]
1 [sec]
2 [sec]
3 [sec]
RM0008