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M451
May. 4, 2018
Page
754
of
1006
Rev.2.08
M4
51
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NICA
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RXEMPTY = 1
RXEMPTY = 1
RXEMPTY = 1
b31|b30...b1|b0
b0
Data 0
RXEMPTY = 0
Example 1
DWIDTH =0
LSB = 1
RX Skew Buffer
RX Shift Register
RX FIFO Buffer
H/W Load
Skew Buffer
into Shift
Register
b1
……………
.b0
b32
…………
..b32
b33
1. H/W load
Shift Register
into RX Buffer
2. H/W Load
Skew Buffer
into Shift
Register
RXEMPTY = 1
RXEMPTY = 0
RXEMPTY = 0
RXFULL = 1
Example 2
DWIDTH =0
LSB = 1
Data 1
Data N
b31|b30...b1|b0
Data 0
H/W load
Shift
Register
into RX
FIFO
Data 9
1. Read Out by
User
2. Repeat
Receive Data
into RX FIFO
Data 1
Data 2
Data 3
Data 4
Data 5
Data 6
Data 7
Data 8
RXEMPTY = 0
RXFULL = 1
RXOVIF = 1
Data 1
Data 2
Data 3
Data 4
Data 5
Data 6
Data 7
Data 8
RX Shift Register
RX FIFO Buffer
H/W Load 32
bits into
Shift Register
The 9th Data
can not load
into RX FIFO
Buffer when
RX FIFO Full
Figure 6.16-19 Receive FIFO Buffer Example
In Slave mode, during transmission operation, when data is written to the SPI_TX register by
software, the data will be loaded into transmit FIFO buffer and the TXEMPTY (SPI_STATUS[16])
will be set to 0. The transmission will start when the slave device receives clock signal from
master. Data can be written to SPI_TX register as long as the TXFULL (SPI_STATUS[17]) is 0.
After all data have been drawn out by the SPI transmission logic unit and the SPI_TX register is
not updated by software, the TXEMPTY (SPI_STATUS[16]) will be set to 1.
If there is no any data written to the SPI_TX register, the transmit underflow flag, TXUFIF
(SPI_STATUS[19]) will be set to 1 when the slave selection signal is active. The output data will
be held by TXUFPOL (SPI_FIFOCTL[6]) setting during this transfer until the slave selection signal
goes to inactive state. When the transmit underflow event occurs, the slave under run flag,
SLVURIF (SPI_STATUS[7]), will be set to 1 as SPIn_SS goes to inactive state.
SPIn_SS
SPIn_CLK
SPIn_MISO
TXEMPTY
SLVURIF
TXUFPOL
TXUFIF
Data 0 is written
into FIFO Buffer
Data 0
Read & Clear by
User
Figure 6.16-20 TX Underflow Event and Slave Under Run Event (Slave 3-Wire Mode Disabled)
Содержание ARM Cortex NuMicro M451 Series
Страница 301: ...M451 May 4 2018 Page 301 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL...
Страница 324: ...M451 May 4 2018 Page 324 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL Figure 6 4 18 Checksum Calculation Flow...
Страница 355: ...M451 May 4 2018 Page 355 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL 2 0 Reserved Reserved...
Страница 625: ...M451 May 4 2018 Page 625 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL 00 5 bits 01 6 bits 10 7 bits 11 8 bits...
Страница 721: ...M451 May 4 2018 Page 721 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL the SCL line 1 0 Reserved Reserved...
Страница 1001: ...M451 May 4 2018 Page 1001 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL LQFP 64L 10x10x1 4 mm footprint 2 0 mm 9 2...
Страница 1002: ...M451 May 4 2018 Page 1002 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL LQFP 64L 7x7x1 4 mm footprint 2 0 mm 9 3...
Страница 1003: ...M451 May 4 2018 Page 1003 of 1006 Rev 2 08 M451 SERIES TECHNICAL REFERENCE MANUAL LQFP 48L 7x7x1 4mm footprint 2 0mm 9 4...