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/* *****************************************************************************
* The MIT License
*
* Copyright (c) 2010 Perry Hung.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* ****************************************************************************/
/**
* @brief libmaple serial peripheral interface (SPI) definitions
*
* Initial implementation for the SPI interface.
*
* This driver implements only the bare essentials of a polling driver at the
* moment. Master mode only, 8-bit data frames, and polling.
*
* The caller is responsible for controlling the chip select line.
*
* TODO: interrupt based driver, DMA.
*
*/
#include "libmaple.h"
#include "gpio.h"
#include "rcc.h"
#include "spi.h"
typedef struct spi_dev {
SPI *base;
GPIO_Port *port;
uint8 sck_pin;
uint8 miso_pin;
uint8 mosi_pin;
} spi_dev;
static const spi_dev spi_dev1 = {
.base = (SPI*)SPI1_BASE,
.port = GPIOA_BASE,
.sck_pin = 5,
.miso_pin = 6,
.mosi_pin = 7
};
static const spi_dev spi_dev2 = {
.base = (SPI*)SPI2_BASE,
.port = GPIOB_BASE,
.sck_pin = 13,
.miso_pin = 14,
.mosi_pin = 15
};
static void spi_gpio_cfg(const spi_dev *dev);
/**
* @brief Initialize a spi peripheral
* @param spi_num which spi to turn on, SPI1 or SPI2?
* @param prescale prescale factor on the input clock.
* @param endian data frame format (LSBFIRST?)
* @param mode SPI mode number
*/
void spi_init(uint32 spi_num,
uint32 prescale,
uint32 endian,
uint32 mode) {
ASSERT(spi_num == 1 || spi_num == 2);
ASSERT(mode < 4);
SPI *spi;
uint32 cr1 = 0;
switch (spi_num) {
case 1:
/* limit to 18 mhz max speed */
ASSERT(prescale != CR1_BR_PRESCALE_2);
spi = (SPI*)SPI1_BASE;
rcc_enable_clk_spi1();
spi_gpio_cfg(&spi_dev1);
break;
case 2:
spi = (SPI*)SPI2_BASE;
rcc_enable_clk_spi2();
spi_gpio_cfg(&spi_dev2);
break;
}
cr1 = prescale | endian | mode | CR1_MSTR | CR1_SSI | CR1_SSM;
spi->CR1 = cr1;
/* Peripheral enable */
spi->CR1 |= CR1_SPE;
}
/**
* @brief SPI synchronous 8-bit write, blocking.
* @param spi_num which spi to send on
* @return data shifted back from the slave
*/
void spi_tx(uint32 spi_num, uint8 data) {
SPI *spi;
ASSERT(spi_num == 1 || spi_num == 2);
spi = (spi_num == 1) ? (SPI*)SPI1_BASE : (SPI*)SPI2_BASE;
spi->DR = data;
while (!(spi->SR & SR_TXE) || (spi->SR & SR_BSY))
;
}
static void spi_gpio_cfg(const spi_dev *dev) {
gpio_set_mode(dev->port, dev->sck_pin, GPIO_MODE_AF_OUTPUT_PP);
gpio_set_mode(dev->port, dev->miso_pin, GPIO_MODE_AF_OUTPUT_PP);
gpio_set_mode(dev->port, dev->mosi_pin, GPIO_MODE_AF_OUTPUT_PP);
}
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