• Slave select (SS)
• Serial clock (SPSCK)
• Master out/slave in (MOSI)
• Master in/slave out (MISO)
An SPI transfer is initiated in the master SPI device by reading the SPI status register
(SPIx_S) when S[SPTEF] = 1 and then writing data to the transmit data buffer (write to
SPIx_DH:SPIx_DL). When a transfer is complete, received data is moved into the
receive data buffer. The SPIx_DH:SPIx_DL registers act as the SPI receive data buffer
for reads and as the SPI transmit data buffer for writes.
The Clock Phase Control (CPHA) and Clock Polarity Control (CPOL) bits in the SPI
Control Register 1 (SPIx_C1) select one of four possible clock formats to be used by the
SPI system. The CPOL bit simply selects a non-inverted or inverted clock. C1[CPHA] is
used to accommodate two fundamentally different protocols by sampling data on odd
numbered SPSCK edges or on even numbered SPSCK edges.
The SPI can be configured to operate as a master or as a slave. When the MSTR bit in
SPI Control Register 1 is set, master mode is selected; when C1[MSTR] is clear, slave
mode is selected.
31.4.2 Master mode
The SPI operates in master mode when C1[MSTR] is set. Only a master SPI module can
initiate transmissions. A transmission begins by reading the SPIx_S register while
S[SPTEF] = 1 and writing to the master SPI data registers. If the shift register is empty,
the byte immediately transfers to the shift register. The data begins shifting out on the
MOSI pin under the control of the serial clock.
• SPSCK
• The SPR3, SPR2, SPR1, and SPR0 baud rate selection bits in conjunction with
the SPPR2, SPPR1, and SPPR0 baud rate preselection bits in the SPI Baud Rate
register control the baud rate generator and determine the speed of the
transmission. The SPSCK pin is the SPI clock output. Through the SPSCK pin,
the baud rate generator of the master controls the shift register of the slave
peripheral.
• MOSI, MISO pin
Chapter 31 Serial Peripheral Interface (SPI)
MKW01Z128 MCU Reference Manual, Rev. 3, 04/2016
Freescale Semiconductor, Inc.
597
Содержание MKW01Z128
Страница 7: ...MKW01xxRM Reference Manual Rev 3 04 2016 viii Freescale Semiconductor Inc...
Страница 11: ...MKW01xxRM Reference Manual Rev 3 04 2016 xii Freescale Semiconductor Inc...
Страница 31: ...MKW01Z128 Pins and Connections MKW01xxRM Reference Manual Rev 3 04 2016 2 8 Freescale Semiconductor Inc...
Страница 129: ...MKW01Z128 Transceiver MCU SPI Interface MKW01xxRM Reference Manual Rev 3 04 2016 8 6 Freescale Semiconductor Inc...
Страница 130: ...MKW01xxRM Reference Manual Rev 3 04 2016 Freescale Semiconductor Inc A 1 Appendix A MKW01Z128 MCU Reference Manual...
Страница 131: ...MKW01Z128 MCU Reference Manual MKW01xxRM Reference Manual Rev 3 04 2016 A 2 Freescale Semiconductor Inc...
Страница 133: ...MKW01Z128 MCU Reference Manual Rev 3 04 2016 2 Freescale Semiconductor Inc...
Страница 221: ...Private Peripheral Bus PPB memory map MKW01Z128 MCU Reference Manual Rev 3 04 2016 90 Freescale Semiconductor Inc...
Страница 233: ...Module clocks MKW01Z128 MCU Reference Manual Rev 3 04 2016 102 Freescale Semiconductor Inc...
Страница 255: ...Module operation in low power modes MKW01Z128 MCU Reference Manual Rev 3 04 2016 124 Freescale Semiconductor Inc...
Страница 279: ...Functional description MKW01Z128 MCU Reference Manual Rev 3 04 2016 148 Freescale Semiconductor Inc...
Страница 305: ...Functional description MKW01Z128 MCU Reference Manual Rev 3 04 2016 174 Freescale Semiconductor Inc...
Страница 325: ...Functional description MKW01Z128 MCU Reference Manual Rev 3 04 2016 194 Freescale Semiconductor Inc...
Страница 379: ...Application information MKW01Z128 MCU Reference Manual Rev 3 04 2016 248 Freescale Semiconductor Inc...
Страница 387: ...Memory map register descriptions MKW01Z128 MCU Reference Manual Rev 3 04 2016 256 Freescale Semiconductor Inc...
Страница 465: ...Functional Description MKW01Z128 MCU Reference Manual Rev 3 04 2016 334 Freescale Semiconductor Inc...
Страница 501: ...Initialization Application information MKW01Z128 MCU Reference Manual Rev 3 04 2016 370 Freescale Semiconductor Inc...
Страница 513: ...Interrupts MKW01Z128 MCU Reference Manual Rev 3 04 2016 382 Freescale Semiconductor Inc...
Страница 517: ...Functional description MKW01Z128 MCU Reference Manual Rev 3 04 2016 386 Freescale Semiconductor Inc...
Страница 611: ...Application information MKW01Z128 MCU Reference Manual Rev 3 04 2016 480 Freescale Semiconductor Inc...
Страница 633: ...CMP Trigger Mode MKW01Z128 MCU Reference Manual Rev 3 04 2016 502 Freescale Semiconductor Inc...
Страница 643: ...Functional description MKW01Z128 MCU Reference Manual Rev 3 04 2016 512 Freescale Semiconductor Inc...
Страница 671: ...Functional description MKW01Z128 MCU Reference Manual Rev 3 04 2016 540 Freescale Semiconductor Inc...
Страница 803: ...Functional description MKW01Z128 MCU Reference Manual Rev 3 04 2016 672 Freescale Semiconductor Inc...
Страница 843: ...Functional description MKW01Z128 MCU Reference Manual Rev 3 04 2016 712 Freescale Semiconductor Inc...
Страница 877: ...Initialization application information MKW01Z128 MCU Reference Manual Rev 3 04 2016 746 Freescale Semiconductor Inc...