Emmc4.4 Emmc4.5
特性:
1 background operation
Most time-consuming operations are due to eMMC internal time Flash Data
management (Garbage collection, wear leveling, bad block management, …)
– Device indicates to the Host the criticality of its need for internal
background maintenance operation by the value in the BKOPS_STATUS
(ECSD[246]) register
– When Host can allocates an extended period of inactivity, it initiates Device
background operation by writing any value to BKOP_START (ECSD[164])
register
• i.e. CMD6 with argument = (0x 03A4 FF00)
– Host may use high priority interrupt command to stop the background
2 high priority interrupt (HPI)
– During a large multiple-block Write operation, data transfer can be terminated by a Stop
command (CMD12), but there may still be an extended period of BUSY time necessary
to complete the Write operation on the data already transferred
– HPI interrupts this process and returns the Device to Trans state such that the Host can
send a Read command to retrieve high-priority data
– The CORRECTLY_PRG_SECTORS_NUM field (EXT_CSD bytes [245:242]) indicates
the number of 512B sectors successfully written to the e·MMC when the Write operation is
interrupted by HPI -- Host can restart the Write operation with the correct address
offset based on this information