Information

Enhanced Secure Digital Host Controller
MPC8308 PowerQUICC II Pro Processor Reference Manual, Rev. 1
11-48 Freescale Semiconductor
For some scenarios, the response timeout is expected. For instance, after all cards respond to CMD3 and
go to the standby state, no response to the host when CMD2 is sent. The host driver should manage false
errors similar to this with caution.
11.6.2 Card Identification Mode
When a card is inserted to the socket or the card was reset by the host, the host needs to validate the
operation voltage range, identify the cards, and request the cards to publish the relative card address (RCA)
or to set the RCA for the MMCs.
11.6.2.1 Card Detect
See Figure 11-26 for a flow diagram showing the detection of MMC, SDIO, and SD cards using the
eSDHC.
Figure 11-26. Flow Diagram for Card Detection
• Set IRQSIGEN[CINIEN] to enable card detection interrupt.
• When an interrupt from eSDHC is received, check IRQSTAT[CINS] to see if it is caused by card
insertion.
• Clear the IRQSIGEN[CINIEN] to disable card detection interrupt and ignore all card insertion
interrupt afterwards.
11.6.2.2 Reset
The host consists of the following three types of reset:
• Hardware reset (card and host) which is driven by POR (power on reset).
• Software reset (host only) is proceeded by the write operation on the SYSCTL[RSTD],
SYSCTL[RSTC], or SYSCTL[RSTA] bits to reset the data part, command part, or all parts of the
host controller, respectively.
• Card reset (card only). The command CMD0, GO_IDLE_STATE, is the software reset command
for all types of MMCs and SD memory cards. This command sets each card into idle state
regardless of the current card state. For an SDIO card, CMD52 is used to write I/O reset in CCCR.
Enable card detection IRQ
Wait for eSDHC interrupt
Check CINS bit
Clear CINSIEN to disable
Voltage validation
No card present
(1)
Yes, card present
card detection interrupt
(2)