GD32W51x User Manual
802
If the PWD content is equal to the sent password, then the card will be unlocked and the card-
locked
status bit will be cleared in the status register. If the password is not correct, then the
LOCK_UNLOCK_FAILED error bit will be set in the status register.
23.7.
Specific operations
23.7.1.
SD I/O specific operations
The SD I/O only card and SD I/O combo card support these specific operations:
Read Wait operation
Suspend/resume operation
Interrupts
The SD I/O supports these operations only if the SDIO_DATACTL[11] bit is set, except for
read suspend that does not need specific hardware implementation.
SD I/O read wait operation
The optional Read Wait (RW) operation is defined only for the SD 1-bit and 4-bit modes. The
Read Wait operation allows a host to signal a card that is executing a read multiple (CMD53)
operation to temporarily stall the data transfer while allowing the host to send commands to
any function within the SD I/O card. To determine if a card supports the Read Wait protocol,
the host shall test SRW capability bit in the Card Capability byte of the CCCR. The timing for
Read Wait is based on the Interrupt Period. If a card does not support the Read Wait protocol,
the only means a host has to stall (not abort) data in the middle of a read multiple c ommand
is to control the SDIO_CK. The limitation of this method is that with the clock stopped, the
host cannot issue any commands, and so cannot perform other operations during the delay
time. Read Wait support is mandatory for the card to support suspend/resume.
Read wait control by stopping SDIO_CK
Figure 23-13. Read wait operation using
show the Read Wait mode about stop the SDIO_CK and use SDIO_D[2].
Figure 23-12. Read wait control by stopping SDIO_CK
SDIO_CK
D
Read data 1a
Interrupt period
H
Read data 1b
2 CLK
2 CLK
1 CLK
Содержание GD32W515 Series
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