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
Содержание DSP56367
Страница 16: ...xvi MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Страница 22: ...xxii MOTOROLA List of Figures Figure Number Title Page Number ...
Страница 26: ...xxvi MOTOROLA List of Tables Table Number Title Page Number ...
Страница 148: ...4 6 DSP56367 MOTOROLA Design Considerations PLL Performance Issues ...
Страница 248: ...9 30 DSP56367 MOTOROLA Serial Host Interface SHI Programming Considerations ...
Страница 306: ...10 58 DSP56367 MOTOROLA Enhanced Serial Audio Interface ESAI ESAI Initialization Examples ...
Страница 389: ...Bootstrap ROM Contents MOTOROLA DSP56367 A 15 end ...
Страница 390: ...A 16 DSP56367 MOTOROLA Bootstrap ROM Contents ...
Страница 432: ...C 8 DSP56367 MOTOROLA JTAG BSDL ...
Страница 484: ...D 52 DSP56367 MOTOROLA Programmer s Reference ...
Страница 490: ...E 6 DSP56367 MOTOROLA Power Consumption Benchmark ...
Страница 516: ...F 26 DSP56367 MOTOROLA IBIS Model ...
Страница 522: ...Index 6 MOTOROLA Index ...
Страница 523: ......