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Mini57
Apr. 06, 2017
Page 352 of 475
Rev.1.00
MINI5
7
S
E
RI
E
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TECH
NIC
A
L R
E
F
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RE
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CE
MA
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UA
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needed to set as 1 for the external SPI Slave device whose slave select signal is active low.
The duration between the slave select active edge and the first SPI clock input edge shall over 2
USCI peripheral clock cycles.
The input slave select signal of SPI Slave has to be keep inactive for at least 2 USCI peripheral
clock cycles between two consecutive frames in order to correctly detect the end of a frame.
6.13.5.5 Transmit and Receive Data
The bit length of a transmit/receive data word in SPI protocol of USCI controller is defined in
DWIDTH (USPI_LINECTL[11:8]), and it can be configured up to 16-bit length and not less than 4-
bit length for transmitting for transmitting and receiving data in SPI communication.
The LSB bit (USPI_LINECTL[0]) defines the order of transfer data bit. If the LSB bit is set to 1, the
transmission data sequence is LSB first. If the LSB bit is cleared to 0, the transmission data
sequence is MSB first.
SPI_CLK
(USCIx_CLK)
SPI_MISO
(USCIx_DAT1)
SPI_MOSI
(USCIx_DAT0)
TX[14]
TX[8]
TX[7]
TX[6]
LSB
TX[0]
RX[14]
RX[8]
RX[6]
LSB
RX[0]
MSB
RX[15]
RX[7]
MSB
TX[15]
SPI_SS
(USCIx_CTL0)
Note:
x = 0,1,2
Note:
x = 0, 1
Figure 6.13-10 16-bit data Length in One Word Transaction with MSB First Format
6.13.5.6 Word Suspend
SUSPITV (USPI_PROTCTL[11:8]) provides a configurable suspend interval, 0.5 ~ 15.5 SPI clock
periods, between two successive transaction words in Master mode. The definition of the suspend
interval is the interval between the last clock edge of the preceding transaction word and the first
clock edge
of the following transaction
word. The default
value of SUSPITV
(USPI_PROTCTL[11:8]) is 0x3 (3.5 SPI clock cycles).