Serial Peripheral Interface (SPI)
13 - 6
C2000 Microcontroller Workshop - Communications
Since data is shifted out of the SPIDAT register MSB first, transmission characters of less than 16
bits must be left-justified by the CPU software prior to be written to SPIDAT.
Received data is shifted into SPIDAT from the left, MSB first. However, the entire sixteen bits
of SPIDAT is copied into SPIBUF after the character transmission is complete such that received
characters of less than 16 bits will be right-justified in SPIBUF. The non-utilized higher
significance bits must be masked-off by the CPU software when it interprets the character. For
example, a 9 bit character transmission would require masking-off the 7 MSB’s.
SPI Data Character Justification
Programmable data
length of 1 to 16 bits
Transmitted data of less
than 16 bits must be left
justified
MSB transmitted first
Received data of less
than 16 bits are right
justified
User software must
mask-off unused MSB’s
11001001XXXXXXXX
XXXXXXXX11001001
SPIDAT - Processor #1
SPIDAT - Processor #2
Содержание C2000 Piccolo LaunchPad
Страница 74: ...Interrupts 4 18 C2000 Microcontroller Workshop Reset and Interrupts ...
Страница 100: ...Lab 5 System Initialization 5 26 C2000 Microcontroller Workshop System Initialization ...
Страница 126: ...Lab 6 Analog to Digital Converter 6 26 C2000 Microcontroller Workshop Analog to Digital Converter ...
Страница 218: ...Lab 8 IQmath FIR Filter 8 42 C2000 Microcontroller Workshop Numerical Concepts ...
Страница 236: ...Lab 9 Servicing the ADC with DMA 9 18 C2000 Microcontroller Workshop Direct Memory Access Controller ...
Страница 260: ...Lab 10 CLA Floating Point FIR Filter 10 24 C2000 Microcontroller Workshop Control Law Accelerator ...
Страница 331: ...C2000 Microcontroller Workshop Appendix A Experimenter s Kit A 1 Appendix A Experimenter s Kit ...
Страница 334: ...F28069 controlCARD A 4 C2000 Microcontroller Workshop Appendix A Experimenter s Kit SW2 ...
Страница 336: ...F28035 controlCARD A 6 C2000 Microcontroller Workshop Appendix A Experimenter s Kit SW2 SW3 ...
Страница 338: ...F28335 controlCARD A 8 C2000 Microcontroller Workshop Appendix A Experimenter s Kit LD1 LD2 LD3 SW1 ...