C8051F330DK Silicon Laboratories Inc, C8051F330DK Datasheet - Page 164

DEV KIT FOR C8051F330/F331

C8051F330DK

Manufacturer Part Number
C8051F330DK
Description
DEV KIT FOR C8051F330/F331
Manufacturer
Silicon Laboratories Inc
Type
MCUr
Datasheets

Specifications of C8051F330DK

Contents
Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
Processor To Be Evaluated
C8051F33x
Interface Type
RS-232
Operating Supply Voltage
7 V to 15 V
Silicon Manufacturer
Silicon Labs
Core Architecture
8051
Silicon Core Number
C8051F330
Silicon Family Name
C8051F33x
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
For Use With/related Products
Silicon Laboratories C8051F330, C8051F331
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
Other names
336-1264
C8051F330/1/2/3/4/5
17.5. Serial Clock Timing
Four combinations of serial clock phase and polarity can be selected using the clock control bits in the
SPI0 Configuration Register (SPI0CFG). The CKPHA bit (SPI0CFG.5) selects one of two clock phases
(edge used to latch the data). The CKPOL bit (SPI0CFG.4) selects between an active-high or active-low
clock. Both master and slave devices must be configured to use the same clock phase and polarity. SPI0
should be disabled (by clearing the SPIEN bit, SPI0CN.0) when changing the clock phase or polarity. The
clock and data line relationships for master mode are shown in Figure 17.5. For slave mode, the clock and
data relationships are shown in Figure 17.6 and Figure 17.7. Note that CKPHA must be set to ‘0’ on both
the master and slave SPI when communicating between two of the following devices: C8051F04x,
C8051F06x, C8051F12x, C8051F31x, C8051F32x, and C8051F33x
The SPI0 Clock Rate Register (SPI0CKR) as shown in SFR Definition 17.3 controls the master mode
serial clock frequency. This register is ignored when operating in slave mode. When the SPI is configured
as a master, the maximum data transfer rate (bits/sec) is one-half the system clock frequency or 12.5 MHz,
whichever is slower. When the SPI is configured as a slave, the maximum data transfer rate (bits/sec) for
full-duplex operation is 1/10 the system clock frequency, provided that the master issues SCK, NSS (in 4-
wire slave mode), and the serial input data synchronously with the slave’s system clock. If the master
issues SCK, NSS, and the serial input data asynchronously, the maximum data transfer rate (bits/sec)
must be less than 1/10 the system clock frequency. In the special case where the master only wants to
transmit data to the slave and does not need to receive data from the slave (i.e. half-duplex operation), the
SPI slave can receive data at a maximum data transfer rate (bits/sec) of 1/4 the system clock frequency.
This is provided that the master issues SCK, NSS, and the serial input data synchronously with the slave’s
system clock.
168
NSS (Must Remain High
in Multi-Master Mode)
SCK
(CKPOL=0, CKPHA=0)
SCK
(CKPOL=0, CKPHA=1)
SCK
(CKPOL=1, CKPHA=0)
SCK
(CKPOL=1, CKPHA=1)
MISO/MOSI
Figure 17.5. Master Mode Data/Clock Timing
MSB
Bit 6
Bit 5
Rev. 1.7
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0

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