User's Manual

Bluegiga Technologies Oy
Page 12 of 41
4 Interfaces
4.1 Host interfaces
WF111 can be interfaced by the host using SDIO in 1bit or 4bit mode, SDIO SPI or CSR proprietary CSPI
connection. The host connection buses can be clocked up to 50MHz. Due to the relatively high clock rate, the
bus layout should be done carefully. To prevent radiated emissions and bus errors due to reflections, the host
bus should be kept short, the signals should run over an uninterrupted ground plane and the clock line should
be series terminated with a 22 to 33 ohm resistor as close to the clock output pin of the host processor as
possible.
4.1.1 Host selection
WF111 will default to 1-bit SDIO mode. The host interface can be set with 1-bit SDIO or SDIO SPI commands
to the required mode. After mode selection, it will then remain in that mode until the module is reset either with
the RESET pin or the internal power supply supervisor.
4.1.2 SDIO interface
This is a host interface which allows a Secure Digital Input Output (SDIO) host to gain access to the internals
of the chip. All defined slave modes (SPI, SD 1bit, SD 4bit) are provided.
Two functions are supported:
 Function 0 is mandatory function used for SDIO slave configuration. This contains CCCR, FBR and
CIS. CCCR registers support sleep and wakeup signaling.
 Function 1 provides access to the IEEE 802.11 functionality. Command IO_RW_DIRECT (CMD52) is
used to directly access internal registers. IO_RW_EXTENDED (CMD53) is used for block transfer
to/from module MMU buffers.
Command
SD Mode (1/4 bit)
SDIO SPI Mode
GO_IDLE_STATE (CMD0)
Y
Y
SEND_RELATIVE_ADDR (CMD3)
Y
N
IO_SEND_OP_COND (CMD5)
Y
Y
SELECT/DESELECT_CARD (CMD7)
Y
N
GO_INACTIVE_STATE (CMD15)
Y
N
IO_RW_DIRECT (CMD52)
Y
Y
IO_RW_EXTENDED (CMD53)
Y
Y
CRC_ON_OFF (CMD59)
N
Y
Table 6: Supported commands per mode
For more information and detailed descriptions of above functions and commands, see the following
specifications:
 SD Specifications Part 1 Physical Layer Specification v.1.10