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MibSPI Operation Modes
Multi-Buffer Serial Peripheral Interface (MibSPI) (SPNU217B)
9
Figure 3.
MibSPI Four-Pin Option with SPISCS
To use the SPISCS [0] as a chip select, the slave SPISCS [0] pin must be
configured as MibSPI functional (SPIPC6.4 = 1). In this mode, an active low
signal on the SPISCS [0] pin will allow the slave SPI to transfer data to the
serial data line. An inactive high signal will put the slave SPI’s serial output
pin in a high-impedance state. Therefore many slave devices can be tied
together on the network, but only one slave at a time is allowed to talk. While
the slave is not selected, no shifting or interrupts will occur.
MibSPI mode
In MibSPI mode, the SPISCS [7:0] pins that are going to be used, must be
configured as functional (SPIPC6.[11:4]). The default pattern to be put on the
SPISCS [7:0] when all the slave are deactivate is set in the SPICRTL6
register. This pattern allows a different slave with different chip-select polarity
to be activated by the MibSPI.
During transmission, the CSNR field of the SPIDAT1 register or of the current
buffer is applied on the pins, this pattern will select the slave to which the
transmission is dedicated. (see section 2.9)
2.3.2
Four-Pin Option with SPIENA
To use the SPIENA as a WAIT signal pin, the SPIENA pin must be configured
to be functional (SPIPC6.0 = 1). In this mode, an active low signal on the
MibSPI four pin option (1)
Master
Slave
(Master = 1 ; CLKMOD = 1)
(Master = 0 ; CLKMOD = 0)
SPIDAT1
SPIDAT0
MSB
LSB
MSB
LSB
Write to
SPIDAT1
SPISOMI
SPISIMO
SPISOMI
SPISIMO
SPICLK
SPICLK
SPISCS
SPISCS
Write to SPIDAT1
SPICLK
SPISIMO
SPISOMI
SPICSCS
Содержание TMS470R1x
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