CC2500 datasheet(19/76 Pages) TI

19 / 76 page

CC2500

Preliminary Data Sheet (rev.1.1.)

SWRS040

Page 19 of 77

Figure 5: SmartRF® Studio user interface

10 4-wire Serial Configuration and Data Interface

CC2500 is configured via a simple 4-wire SPI-

compatible interface (SI, SO, SCLK and CSn)

where

CC2500 is the slave. This interface is

also used to read and write buffered data. All

address and data transfer on the SPI interface

is done most significant bit first.

All transactions on the SPI interface start with

a header byte containing a read/write bit, a

burst access bit and a 6-bit address.

During address and data transfer, the CSn pin

(Chip Select, active low) must be kept low. If

CSn goes high during the access, the transfer

will be cancelled. The timing for the address

and data transfer on the SPI interface is

shown in Figure 6 with reference to Table 16.

When CSn goes low, the MCU must wait until

CC2500 SO pin goes low before starting to

transfer the header byte. This indicates that

the voltage regulator has stabilized and the

crystal is running. Unless the chip was in the

SLEEP or XOFF states, the SO pin will always

go low immediately after taking CSn low.

Figure 7 gives a brief overview of different

CC2500 Datasheet(PDF) 19 Page - Texas Instruments