12.3.5 Baud Rate Selection
The SPI module supports 125 different baud rates and four different clock schemes. Depending on whether the
SPI clock is in slave or master mode, the SPICLK pin can receive an external SPI clock signal or provide the SPI
clock signal, respectively.
• In the slave mode, the SPI clock is received on the SPICLK pin from the external source and can be no
greater than the LSPCLK frequency divided by 4.
• In the master mode, the SPI clock is generated by the SPI and is output on the SPICLK pin and can be no
greater than the LSPCLK frequency divided by 4.
Note
The baud rate should be configured to not exceed the maximum rated GPIO toggle frequency. Refer
to the device data sheet for the maximum GPIO toggle frequency
shows how to determine the SPI baud rates.
Example 12-2. Baud Rate Determination
For SPIBRR = 3 to 127:
SPI Baud Rate
LSPCLK
(SPIBRR
1)
=
+
(5)
For SPIBRR = 0, 1, or 2:
SPI Baud Rate
LSPCLK
4
=
(6)
where:
LSPCLK = Low-speed peripheral clock frequency of the device
SPIBRR = Contents of the SPIBRR in the master SPI device
To determine what value to load into SPIBRR, you must know the device system clock (LSPCLK) frequency (that
is device-specific) and the baud rate at which you will be operating.
shows how to calculate the baud rate of the SPI module .
Example 12-3. Baud Rate Calculation
(7)
Serial Peripheral Interface (SPI)
770
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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