SI3050 datasheet(49/128 Pages) SILABS

49 / 128 page

Si3050 + Si3011/18/19

Rev. 1.5

Figure 38. Sample SPI Control Byte for Broadcast Mode (Write Only)

In Figure 37 the CID field is 0. As this field is decremented in LSB to MSB order, the value decrements for each SDI

down the line. The BRCT and R/W bits remain unchanged as the control word passes through the entire chain. A

unique CID is presented to each device, and the device receiving a CID value of 0 is the target of the operation

(channel 0 in this case). Figure 38 illustrates that in broadcast mode, all bits pass through the chain without

permutation.

Figure 39. Write Operation via an 8-bit SPI Port

Figure 40. Read Operation via an 8-bit SPI Port

Figure 39 and Figure 40 illustrate WRITE and READ operations via an 8-bit SPI controller. Each of these

operations are performed as a 3-byte transfer. The CS pin is asserted between each byte. The CS pin must be

asserted before the first falling edge of SCLK after the DATA byte to indicate to the state machine that only one

byte should be transferred. The state of the SDI pin is ignored during the DATA byte of a read operation.

Figure 41. Write Operation via a 16-bit SPI Port

SDI0-15

CONTROL

ADDRESS

DATA [7:0]

CSB

SCLK

SDI

SDO

Hi-Z

CONTROL

ADDRESS

XXXXXXXXXXXX

CSB

SCLK

SDI

SDO

Data [7:0]

X X X X X X X X

CSB

SCLK

SDI

SDO

CONTROL

ADDRESS

Data [7:0]

Hi - Z

Si3050 Datasheet(PDF) 49 Page - Silicon Laboratories