EM351_12 Datasheet, PDF (88/245 Pages) Silicon Laboratories – High-Performance, Integrated ZigBee/802.15.4 System-on-Chip

EM351 / EM357
SCx_RATEEXP
SC1_RATEEXP
Serial Clock Exponential Prescaler Register
SC2_RATEEXP
Serial Clock Exponential Prescaler Register
Address: 0x4000C864 Reset: 0x0
Address: 0x4000C064 Reset: 0x0
31
30
29
28
27
26
25
24
0
0
0
0
0
0
0
0
23
22
21
20
19
18
17
16
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
0
0
0
0
SC_RATEEXP
Bitname
SC_RATEEXP
Bitfield
[3:0]
Access
RW
Description
The exponential component (EXP) of the clock rate in the equation:
rate = 12MHz / ( (LIN + 1) * (2^EXP) )
8.4 SPI - Slave Mode
Both SC1 and SC2 SPI controllers include a SPI slave controller with these features:
 ^{Full duplex operation}
 ^{Up to 5 Mbps data transfer rate}
 ^{Programmable clock polarity and clock phase}
 ^{Selectable data shift direction (either LSB or MSB first)}
 ^{Slave select input}
8.4.1 GPIO Usage
The SPI slave controller uses four signals:
 ^{MOSI (Master Out, Slave In) – inputs serial data from the master}
 ^{MISO (Master In, Slave Out) – outputs serial data to the master}
 ^{SCLK (Serial Clock) – clocks data transfers on MOSI and MISO}
 ^{nSSEL (Slave Select) – enables serial communication with the slave}
Note: The SPI slave controller does not tri-state the MISO signal when slave select is deasserted.
8-14
Final
120-035X-000M