Master SPI Bus Manager

Files
file	mspi-mgr.h
	Master SPI Bus Manager definitions

Macros
#define	MAX_SPI_DEVICES   7

Functions
void	add_to_spi_mgr (uint8_t cs, uint8_t mode, uint16_t baud)
	This function add a device to the SPI device table and calculates the specific checksum. More...
void	change_spi_mode (spi_dev new_config)
	This function changes the SPI configuration. More...

Detailed Description

The various SPI devices are all connected to the SPI Bus (SCK, MOSI/SDA, MISO/SDI) and only separated by the Chip Select. With a high probability, not every SPI Device will use the same SPI Bus configuration (SPI Mode), so you would have to change (or to check) the SPI mode whenever accessing another SPI device. But in higher software layers you are not interested in such details like SPI Mode. Therefore the SPI Bus Manager was implemented, to separate the low level hardware and register level from higher software layers. The SPI Bus Manager holds all devices, which are connected to the SPI Bus. With a checksum he can decide, if the SPI configuration has to change. So in some cases these reconfiguration can be avoid.

Note

If you know what you are doing, it is possible to disable the SPI Bus Manager by setting MSPI_BUS_MANAGER in the mspi-drv.h to 0.

Macro Definition Documentation

#define MAX_SPI_DEVICES   7

Defines the maximum number of SPI devices

Note

In our case we have 7 (2³-1) possible SPI devices, because we are using 3 I/O pins and a BCD-to-decimal encoder for the chip select.

Definition at line 64 of file mspi-mgr.h.

Function Documentation

void add_to_spi_mgr	(	uint8_t	cs,
		uint8_t	mode,
		uint16_t	baud
	)

This function add a device to the SPI device table and calculates the specific checksum.

Parameters

cs	Chip Select: Device ID
mode	Select the (M)SPI mode (MSPI_MODE_0 ... MSPI_MODE_3)
baud	The MSPI BAUD rate. Sometimes it is necessary to reduce the SCK. Use MSPI_BAUD_MAX in common case.

Definition at line 106 of file mspi-drv.c.

Referenced by mspi_init().

void change_spi_mode

(

spi_dev

new_config

)

This function changes the SPI configuration.

Parameters

spi_dev

The specified entry of the SPI Device Table

Definition at line 112 of file mspi-drv.c.

Referenced by mspi_chip_select().