Serial Host Interface
Characteristics Of The SPI Bus
MOTOROLA
DSP56367
9-3
Figure 9-1 Serial Host Interface Block Diagram
9.3
CHARACTERISTICS OF THE SPI BUS
The SPI bus consists of two serial data lines (MISO and MOSI), a clock line (SCK), and a
Slave Select line (SS). During an SPI transfer, a byte is shifted out one data pin while a
different byte is simultaneously shifted in through a second data pin. It can be viewed as two
8-bit shift registers connected together in a circular manner, with one shift register on the
master side and the other on the slave side. Thus the data bytes in the master device and slave
device are exchanged. The MISO and MOSI data pins are used for transmitting and receiving
serial data. When the SPI is configured as a master, MISO is the master data input line, and
MOSI is the master data output line. When the SPI is configured as a slave device, MISO is
the slave data output line, and MOSI is the slave data input line.
DSP
Global
Data
Bus
DSP Accessible
Host Accessible
SCK/SCL
MISO/SDA
MOSI/HA0
SS/HA2
HRX
(FIFO)
HREQ
HCSR
HTX
HCKR
24 BIT
HSAR
Clock
Generator
Controller
Logic
Slave
Address
Recognition
Unit
(SAR)
Pin
Control
Logic
INPUT/OUTPUT Shift Register
(IOSR)
AA0416
DSP
DMA
Data
Bus
Summary of Contents for DSP56367
Page 16: ...xvi MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Page 22: ...xxii MOTOROLA List of Figures Figure Number Title Page Number ...
Page 26: ...xxvi MOTOROLA List of Tables Table Number Title Page Number ...
Page 148: ...4 6 DSP56367 MOTOROLA Design Considerations PLL Performance Issues ...
Page 248: ...9 30 DSP56367 MOTOROLA Serial Host Interface SHI Programming Considerations ...
Page 306: ...10 58 DSP56367 MOTOROLA Enhanced Serial Audio Interface ESAI ESAI Initialization Examples ...
Page 389: ...Bootstrap ROM Contents MOTOROLA DSP56367 A 15 end ...
Page 390: ...A 16 DSP56367 MOTOROLA Bootstrap ROM Contents ...
Page 432: ...C 8 DSP56367 MOTOROLA JTAG BSDL ...
Page 484: ...D 52 DSP56367 MOTOROLA Programmer s Reference ...
Page 490: ...E 6 DSP56367 MOTOROLA Power Consumption Benchmark ...
Page 516: ...F 26 DSP56367 MOTOROLA IBIS Model ...
Page 522: ...Index 6 MOTOROLA Index ...
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