9-22
DSP56367
MOTOROLA
Serial Host Interface
SHI Programming Considerations
Figure 9-11 I
2
C Bus Protocol For Host Read Cycle
Note:
The first data byte in a write-bus cycle can be used as a user-predefined control
byte (e.g., to determine the location to which the forthcoming data bytes should be
transferred).
9.7
SHI PROGRAMMING CONSIDERATIONS
The SHI implements both SPI and I
2
C bus protocols and can be programmed to operate as a
slave device or a single-master device. Once the operating mode is selected, the SHI may
communicate with an external device by receiving and/or transmitting data. Before changing
the SHI operational mode, an SHI individual reset should be generated by clearing the HEN
bit. The following paragraphs describe programming considerations for each operational
mode.
9.7.1
SPI SLAVE MODE
The SPI slave mode is entered by enabling the SHI (HEN=1), selecting the SPI mode
(HI
2
C=0), and selecting the slave mode of operation (HMST=0). The programmer should
verify that the CPHA and CPOL bits (in the HCKR) correspond to the external host clock
phase and polarity. Other HCKR bits are ignored. When configured in the SPI slave mode, the
SHI external pins operate as follows:
•
SCK/SCL is the SCK serial clock input.
•
MISO/SDA is the MISO serial data output.
•
MOSI/HA0 is the MOSI serial data input.
•
SS/HA2 is the SS slave select input.
S
A
A
1
Slave Address
R/W
P
1
Start
Stop
Bit
Bit
Slave Device
ACK from
Master Device
ACK from
No ACK
Data Byte
N = 0 to M
Data Bytes
Last Data Byte
from Master Device
AA0426
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 ...
Page 523: ......