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GD32F20x User Manual
663
completed, the resume is issued to function, causing the data transfer to resume (DF=1).
Figure 24-14. Function2 read cycle inserted during function1 multiple read cycle
CMD
DAT
Read n blocks
CMD(1)
RES
P(1)
CMD52(RAW)
BR=1,BS=1
CMD52(R)
BS=0
Read 1 block
CMD(2)
RES
P(1)
CMD52(RAW)
FS=1,DF=1
Data
Fn1
Data
Fn2
Data
Fn1
Suspend to
function1 is not
accepted
Check status,
bus suspended
Read n blocks to
function 1
Read 1 blocks to
function 2
Resume to
function 1
When the host sends data to the card, the host can suspend the write operation. The
SDIO_CMDCTL[11] bit is set and indicates to the CSM that the current command is a suspend
command. The CSM analyzes the response and when the response is received from the card
(suspend accepted), it acknowledges the DSM that goes Idle after receiving the CRC token
of the current block.
To suspend a read operation, the DSM waits in the WaitR state, when the function to be
suspended sends a complete packet just before stopping the data transaction. The
application should continue reading receive FIFO until the FIFO is empty, and the DSM goes
Idle state automatically.
Interrupts
In order to allow the SD I/O card to interrupt the host, an interrupt function is added to a pin
on the SD interface. Pin number 8, which is used as SDIO_DAT[1] when operating in the 4-
bit SD mode, is used to signal the card’s interrupt to the host. The use of interrupt is optional
for each card or function within a card. The SD I/O interrupt is “level sensitive”, that is, the
interrupt line shall be held active (low) until it is either recognized and acted upon by the host
or de-asserted due to the end of the Interrupt Period. Once the host has serviced the interrupt,
it is cleared via function unique I/O operation.
When setting the SDIO_DATACTL[11] bit SD I/O interrupts can detect on the SDIO_DAT[1]
line.
Figure 24-15. Read Interrupt cycle timing
shows the timing of the interrupt period for single
data transaction read cycles.
Figure 24-15. Read Interrupt cycle timing
SDIO_CLK
DAT0
Command read data
2 CLK
CMD
DAT1
DAT1(mode)
S
E
Response
S
E
Command read data
S
E
Data
S
E
Data
S
E
interrupt
data
data
Содержание GD32F20 Series
Страница 1: ...GigaDevice Semiconductor Inc GD32F20x ARM Cortex M3 32 bit MCU User Manual Revision 2 2 Oct 2019 ...
Страница 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Страница 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Страница 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Страница 385: ...GD32F20x User Manual 385 ...
Страница 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...