Dynamically change SPI clock

Hi Artem,

Artem said:

Question: how to dynamically change the clock of SPI master. I share one SPI for several slaves, each has different speed and own (separate) tasks.

You can write a separate function something like below and pass the "clock-to-be-set" as a parameter.

In sofware you must be knowing to which device you are going to communicate with;So accordingly, you can call this clock-configuration-function for each task.

For example:-
This code snippet is from C6748 starterware. For more info, refer to the package.

// in each task insert a function call like this.

SPIClkConfigure(SOC_SPI_1_REGS, 150000000, 20000000, SPI_DATA_FORMAT0);

/**
* \brief - It will configure the prescalar to generate required spi clock\n.
*
* \param - baseAdd is Memory Address of the SPI instance used\n.
* \param - moduleClk is the input clk to SPI module from PLL\n.
* \param - spiClk is the spi bus speed\n.
* \param - dataFormat is instance of the data format register used\n.
*
* \return none.
**/
void SPIClkConfigure(unsigned int baseAdd, unsigned int moduleClk,
unsigned int spiClk, unsigned int dataFormat)
{
unsigned int prescale;

prescale = (moduleClk/spiClk) - 1;

HWREG(baseAdd + SPI_SPIFMT(dataFormat)) = \
(SPI_SPIFMT_PRESCALE & (prescale << SPI_SPIFMT_PRESCALE_SHIFT));
}