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Document No. 002-14949 Rev. *E
Page 42 of 113
PRELIMINARY
CYW43353
Figure 18. Signal Connections to SDIO Host (SD 1-Bit Mode)
Note:
Per Section 6 of the SDIO specification, pull-ups in the 10 k
Ω
to 100 k
Ω
range are required on the four DATA lines and the CMD
line. This requirement must be met during all operating states either through the use of external pull-up resistors or through proper
programming of the SDIO host’s internal pull-ups
9.2 Generic SPI Mode
In addition to the full SDIO mode, the CYW43353 includes the option of using the simplified generic SPI (gSPI) interface/protocol.
Characteristics of the gSPI mode include:
■
Supports up to 48 MHz operation
■
Supports fixed delays for responses and data from device
■
Supports alignment to host gSPI frames (16 or 32 bits)
■
Supports up to 2 KB frame size per transfer
■
Supports little endian (default) and big endian configurations
■
Supports configurable active edge for shifting
■
Supports packet transfer through DMA for WLAN
gSPI mode is enabled using the strapping option pins strap_host_ifc_[3:1].
Figure 19. Signal Connections to SDIO Host (gSPI Mode)
SD
Host
CYW43353
CLK
CMD
DATA
IRQ
RW
SD
Host
CYW43353
SCLK
DI
DO
IRQ
CS