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Merge pull request #409 from ADVANSEE/cc2538-spi

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cc2538: spi: Bug fix and various improvements
This commit is contained in:
George Oikonomou 2013-11-20 06:51:26 -08:00
parent 38e8d8bde0 e8a8870d1d
commit f13af20f12
2 changed files with 52 additions and 9 deletions
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46
cpu/cc2538/dev/spi.c
View file

@ -35,12 +35,27 @@
*/
#include "contiki.h"
#include "reg.h"
#include "spi-arch.h"
#include "dev/ioc.h"
#include "dev/sys-ctrl.h"
#include "dev/spi.h"
#include "dev/ssi.h"
#include "dev/gpio.h"
#include "spi-arch.h"
/* Default: Motorola mode 3 with 8-bit data words */
#ifndef SPI_CONF_PHASE
#define SPI_CONF_PHASE SSI_CR0_SPH
#endif
#ifndef SPI_CONF_POLARITY
#define SPI_CONF_POLARITY SSI_CR0_SPO
#endif
#ifndef SPI_CONF_DATA_SIZE
#define SPI_CONF_DATA_SIZE 8
#endif
#if SPI_CONF_DATA_SIZE < 4 || SPI_CONF_DATA_SIZE > 16
#error SPI_CONF_DATA_SIZE must be set between 4 and 16 inclusive.
#endif
/**
* \brief Initialize the SPI bus.
@ -51,13 +66,15 @@
* CC2538_SPI_MISO_PORT_NUM CC2538_SPI_MISO_PIN_NUM
* CC2538_SPI_SEL_PORT_NUM CC2538_SPI_SEL_PIN_NUM
*
* This sets the SPI data width to 8 bits and the mode to Freescale mode 3.
* This sets the mode to Motorola SPI with the following format options:
* SPI_CONF_PHASE: 0 or SSI_CR0_SPH
* SPI_CONF_POLARITY: 0 or SSI_CR0_SPO
* SPI_CONF_DATA_SIZE: 4 to 16 bits
*/
void
spi_init(void)
{
/* Enable the SSI peripheral */
REG(SYS_CTRL_RCGCSSI) |= 1;
spi_enable();
/* Start by disabling the peripheral before configuring it */
REG(SSI0_BASE + SSI_CR1) = 0;
@ -86,13 +103,24 @@ spi_init(void)
/* Configure the clock */
REG(SSI0_BASE + SSI_CPSR) = 2;
/* Put the ssi in motorola SPI mode with 8 bit data */
REG(SSI0_BASE + SSI_CR0) = SSI_CR0_SPH_M | SSI_CR0_SPO_M | (7);
/* Put the ssi in Motorola SPI mode using the provided format options */
REG(SSI0_BASE + SSI_CR0) = SPI_CONF_PHASE | SPI_CONF_POLARITY | (SPI_CONF_DATA_SIZE - 1);
/* Enable the SSI */
REG(SSI0_BASE + SSI_CR1) |= SSI_CR1_SSE;
/* Clear the RX FIFO */
SPI_WAITFOREORx();
}
/*---------------------------------------------------------------------------*/
void
spi_enable(void)
{
/* Enable the clock for the SSI peripheral */
REG(SYS_CTRL_RCGCSSI) |= 1;
}
/*---------------------------------------------------------------------------*/
void
spi_disable(void)
{
/* Gate the clock for the SSI peripheral */
REG(SYS_CTRL_RCGCSSI) &= ~1;
}
/** @} */

15
cpu/cc2538/spi-arch.h
View file

@ -57,6 +57,21 @@
#define SPI_WAITFOREORx() do { \
while(!(REG(SSI0_BASE + SSI_SR) & SSI_SR_RNE)); \
} while (0)
/*---------------------------------------------------------------------------*/
/** \name Arch-specific SPI functions
* @{
*/
/** \brief Enables the SPI peripheral
*/
void spi_enable(void);
/** \brief Disables the SPI peripheral
* \note Call this function to save power when the SPI is unused.
*/
void spi_disable(void);
/** @} */
#endif /* SPI_ARCH_H_ */