SI4463 datasheet(18/53 Pages) SILABS

18 / 53 page

Si4463/61/60-C

Rev 1.0

3.2. Fast Response Registers

The fast response registers are registers that can be read immediately without the requirement to monitor and

check CTS. There are four fast response registers that can be programmed for a specific function. The fast

response registers can be read through API commands, 0x50 for Fast Response A, 0x51 for Fast Response B,

0x53 for Fast Response C, and 0x57 for Fast Response D. The fast response registers can be configured by the

“FRR_CTL_X_MODE” properties.

The fast response registers may be read in a burst fashion. After the initial 16 clock cycles, each additional eight

clock cycles will clock out the contents of the next fast response register in a circular fashion. The value of the

FRRs will not be updated unless NSEL is toggled.

3.3. Operating Modes and Timing

The primary states of the Si446x are shown in Figure 6. The shutdown state completely shuts down the radio to

minimize current consumption. Standby/Sleep, SPI Active, Ready, TX Tune, and RX tune are available to optimize

the current consumption and response time to RX/TX for a given application. API commands START_RX,

START_TX, and CHANGE_STATE control the operating state with the exception of shutdown which is controlled

by SDN, pin 1. Table 10 shows each of the operating modes with the time required to reach either RX or TX mode

as well as the current consumption of each mode. The times in Table 9 are measured from the rising edge of nSEL

until the chip is in the desired state. Note that these times are indicative of state transition timing but are not

guaranteed and should only be used as a reference data point. An automatic sequencer will put the chip into RX or

TX from any state. It is not necessary to manually step through the states. To simplify the diagram it is not shown

but any of the lower power states can be returned to automatically after RX or TX.

Figure 6. State Machine Diagram

SI4463 Fiches technique(PDF) 18 Page - Silicon Laboratories