nes-proj/cpu/cc2538/dev/spi.c

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/*
* Copyright (c) 2013, University of Michigan.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/**
* \addtogroup cc2538-spi
* @{
*
* \file
* Implementation of the cc2538 SPI peripheral
*/
#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"
#define SPI_CLK_PORT_BASE GPIO_PORT_TO_BASE(SPI_CLK_PORT)
#define SPI_CLK_PIN_MASK GPIO_PIN_MASK(SPI_CLK_PIN)
#define SPI_MOSI_PORT_BASE GPIO_PORT_TO_BASE(SPI_MOSI_PORT)
#define SPI_MOSI_PIN_MASK GPIO_PIN_MASK(SPI_MOSI_PIN)
#define SPI_MISO_PORT_BASE GPIO_PORT_TO_BASE(SPI_MISO_PORT)
#define SPI_MISO_PIN_MASK GPIO_PIN_MASK(SPI_MISO_PIN)
/**
* \brief Initialize the SPI bus.
*
* This SPI init() function uses the following #defines to set the pins:
* SPI_CLK_PORT SPI_CLK_PIN
* SPI_MOSI_PORT SPI_MOSI_PIN
* SPI_MISO_PORT SPI_MISO_PIN
*
* This sets the mode to Motorola SPI with the following format options:
* Clock phase: 1; data captured on second (rising) edge
* Clock polarity: 1; clock is high when idle
* Data size: 8 bits
*/
void
spi_init(void)
{
spi_enable();
/* Start by disabling the peripheral before configuring it */
REG(SSI0_BASE + SSI_CR1) = 0;
/* Set the IO clock as the SSI clock */
REG(SSI0_BASE + SSI_CC) = 1;
/* Set the mux correctly to connect the SSI pins to the correct GPIO pins */
ioc_set_sel(SPI_CLK_PORT, SPI_CLK_PIN, IOC_PXX_SEL_SSI0_CLKOUT);
ioc_set_sel(SPI_MOSI_PORT, SPI_MOSI_PIN, IOC_PXX_SEL_SSI0_TXD);
REG(IOC_SSIRXD_SSI0) = (SPI_MISO_PORT * 8) + SPI_MISO_PIN;
/* Put all the SSI gpios into peripheral mode */
GPIO_PERIPHERAL_CONTROL(SPI_CLK_PORT_BASE, SPI_CLK_PIN_MASK);
GPIO_PERIPHERAL_CONTROL(SPI_MOSI_PORT_BASE, SPI_MOSI_PIN_MASK);
GPIO_PERIPHERAL_CONTROL(SPI_MISO_PORT_BASE, SPI_MISO_PIN_MASK);
/* Disable any pull ups or the like */
ioc_set_over(SPI_CLK_PORT, SPI_CLK_PIN, IOC_OVERRIDE_DIS);
ioc_set_over(SPI_MOSI_PORT, SPI_MOSI_PIN, IOC_OVERRIDE_DIS);
ioc_set_over(SPI_MISO_PORT, SPI_MISO_PIN, IOC_OVERRIDE_DIS);
/* Configure the clock */
REG(SSI0_BASE + SSI_CPSR) = 2;
/* Configure the default SPI options.
* mode: Motorola frame format
* clock: High when idle
* data: Valid on rising edges of the clock
* bits: 8 byte data
*/
REG(SSI0_BASE + SSI_CR0) = SSI_CR0_SPH | SSI_CR0_SPO | (0x07);
/* Enable the SSI */
REG(SSI0_BASE + SSI_CR1) |= SSI_CR1_SSE;
}
/*---------------------------------------------------------------------------*/
void
spi_cs_init(uint8_t port, uint8_t pin)
{
GPIO_SOFTWARE_CONTROL(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin));
ioc_set_over(port, pin, IOC_OVERRIDE_DIS);
GPIO_SET_OUTPUT(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin));
GPIO_SET_PIN(GPIO_PORT_TO_BASE(port), GPIO_PIN_MASK(pin));
}
/*---------------------------------------------------------------------------*/
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;
}
/*---------------------------------------------------------------------------*/
void spi_set_mode(uint32_t frame_format, uint32_t clock_polarity, uint32_t clock_phase, uint32_t data_size)
{
/* Disable the SSI peripheral to configure it */
REG(SSI0_BASE + SSI_CR1) = 0;
/* Configure the SSI options */
REG(SSI0_BASE + SSI_CR0) = clock_phase | clock_polarity | frame_format | (data_size - 1);
/* Re-enable the SSI */
REG(SSI0_BASE + SSI_CR1) |= SSI_CR1_SSE;
}
/** @} */