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M451
May. 4, 2018
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(SPI_STATUS[1]) will be set to 1. The unit transfer interrupt event will generate an interrupt to
CPU if the unit transfer interrupt enable bit UNITIEN (SPI_CTL[17]) is set. The unit transfer
interrupt flag can be cleared only by writing 1 to it.
SPI slave selection active/inactive interrupt
In Slave mode, the slave selection active/inactive interrupt flag, SSACTIF (SPI_STATUS[2]) and
SSINAIF (SPI_STATUS[3]), will be set to 1 when the SPIEN (SPI_CTL[0]) and SLAVE
(SPI_CTL[18]) are set to 1 and the slave selection signal goes to active/inactive state. The SPI
controller will issue an interrupt if the SSINAIEN (SPI_SSCTL[13]) or SSACTIEN
(SPI_SSCTL[12]) is set to 1.
Slave time-out interrupt
In Slave mode, there is slave time-out function for user to know that there is serial clock input but
one transaction is not finished over the period of SLVTOCNT (SPI_SSCTL[31:16]) basing on
Slave peripheral clock.
When the slave selection signal is active and the value of SLVTOCNT (SPI_SSCTL[31:16]) is not
0, the slave time-out counter in the SPI controller logic will start after the serial clock input. This
counter will be cleared after one transaction done or the SLVTOCNT (SPI_SSCTL[31:16]) is set
to 0. If the value of the time-out counter is greater than or equal to the value of SLVTOCNT
(SPI_SSCTL[31:16]) before one transaction done, the slave time-out event occurs and the
SLVTOIF (SPI_STATUS[5]) will be set to 1. The SPI controller will issue an interrupt if the
SLVTOIEN (SPI_SSCTL[5]) is set to 1.
Slave bit count error interrupt
In Slave mode, if the transmit/receive bit count mismatch with the DWIDTH (SPI_CTL[12:8]) when
the slave selection line goes to inactive state, the SLVBEIF (SPI_STATUS[6]) will be set to 1. The
uncompleted transaction will be dropped from TX and RX shift registers. The SPI controller will
issue an interrupt if the SLVBEIEN (SPI_SSCTL[8]) is set to 1.
Note:
If the slave selection signal is active but there is no any serial clock input, the SLVBEIF
(SPI_STATUS[6]) will be set to 1 when the slave selection signal goes to inactive state.
TX underflow interrupt
In SPI Slave mode, if there is no any data is written to the SPI_TX register, the TXUFIF
(SPI_STATUS[19]) will be set to 1 when the slave selection signal is active. The SPI controller will
issue a TX underflow interrupt if the TXUFIEN (SPI_FIFOCTL[7]) is set to 1.
Slave TX under run interrupt
If the TX underflow event occurs, the SLVURIF (SPI_STATUS[7]) will be set to 1 when SPIn_SS
goes to inactive state. The SPI controller will issue a TX under run interrupt if the SLVURIEN
(SPI_SSCTL[9]) is set to 1.
Note:
In Slave 3-Wire mode, the slave selection signal is considered active all the time so that
user shall poll the TXUFIF (SPI_STATUS[19]) to know if there is TX underflow event or not.
Receive Overrun interrupt
In Slave mode, if the receive FIFO buffer contains 8 unread data, the RXFULL (SPI_STATUS[9])
flag will be set to 1 in SPI0 (4 unread data in SPI1/2) and the RXOVIF (SPI_STATUS[11]) will be
set 1 if there is more serial data is received from SPI bus and follow-up data will be dropped. The
SPI controller will issue an interrupt if the RXOVIEN (SPI_FIFOCTL[5]) is set to 1.
Receive FIFO time-out interrupt
If there is a received data in the FIFO buffer and it is not read by software over 64 SPI peripheral
clock periods in Master mode or over 576 SPI peripheral clock periods in Slave mode, it will send
a RX time-out interrupt to the system if the RX time-out interrupt enable bit, RXTOIEN
(SPI_FIFOCTL[4]), is set to 1.
Содержание ARM Cortex NuMicro M451 Series
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