spi.c
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/*
* Copyright (C) 2015 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for more
* details.
*/
/**
* @ingroup cpu_lpc11u34
* @{
*
* @file
* @brief Low-level GPIO driver implementation
*
* @author Paul RATHGEB <paul.rathgeb@skynet.be>
*
* @}
*/
#include "cpu.h"
#include "board.h"
#include "mutex.h"
#include "periph/spi.h"
#include "periph_conf.h"
#include "thread.h"
#include "sched.h"
/* guard file in case no SPI device is defined */
#if SPI_NUMOF
/**
* @brief Array holding one pre-initialized mutex for each SPI device
*/
static mutex_t locks[] = {
#if SPI_0_EN
[SPI_0] = MUTEX_INIT,
#endif
#if SPI_1_EN
[SPI_1] = MUTEX_INIT,
#endif
};
int spi_init_master(spi_t dev, spi_conf_t conf, spi_speed_t speed)
{
LPC_SSPx_Type *spi;
/* power on the SPI device */
spi_poweron(dev);
/* configure SCK, MISO and MOSI pin */
spi_conf_pins(dev);
switch(dev) {
#if SPI_0_EN
case SPI_0:
spi = LPC_SSP0;
break;
#endif
#if SPI_1_EN
case SPI_1:
spi = LPC_SSP1;
break;
#endif
default:
return -1;
}
/* Master mode, SPI disabled */
spi->CR1 = 0;
/* Base clock frequency : 12MHz */
spi->CPSR = 4;
/* configure bus clock speed */
switch (speed) {
case SPI_SPEED_100KHZ:
spi->CR0 |= (119 << 8);
break;
case SPI_SPEED_400KHZ:
spi->CR0 |= (29 << 8);
break;
case SPI_SPEED_1MHZ:
spi->CR0 |= (11 << 8);
break;
case SPI_SPEED_5MHZ:
spi->CR0 |= (2 << 8); /* Actual : 4MHz */
break;
case SPI_SPEED_10MHZ:
spi->CR0 |= (0 << 8); /* Actual : 12MHz */
break;
}
/* Set mode and 8-bit transfer */
spi->CR0 |= 0x07 | (conf << 6);
/* Enable SPI */
spi->CR1 |= (1 << 1);
/* Wait while the BUSY flag is set */
while(spi->SR & (1 << 4)) {}
/* Clear the RX FIFO */
while(spi->SR & (1 << 2)) {
spi->DR;
}
return 0;
}
int spi_init_slave(spi_t dev, spi_conf_t conf, char (*cb)(char data))
{
/* Slave mode not supported */
return -1;
}
int spi_conf_pins(spi_t dev)
{
switch (dev) {
#if SPI_0_EN
case SPI_0:
/* SPI0 : MISO */
LPC_IOCON->PIO0_8 |= 1;
/* SPI0 : MOSI */
LPC_IOCON->PIO0_9 |= 1;
/* SPI0 : SCK */
LPC_IOCON->SWCLK_PIO0_10 |= 2;
break;
#endif
#if SPI_1_EN
case SPI_1:
/* SPI1 : MISO */
LPC_IOCON->PIO1_21 |= 2;
/* SPI1 : MOSI */
LPC_IOCON->PIO0_21 |= 2;
/* SPI1 : SCK */
LPC_IOCON->PIO1_20 |= 2;
#endif
default:
return -1;
}
return 0;
}
int spi_acquire(spi_t dev)
{
if ((unsigned int)dev >= SPI_NUMOF) {
return -1;
}
mutex_lock(&locks[dev]);
return 0;
}
int spi_release(spi_t dev)
{
if ((unsigned int)dev >= SPI_NUMOF) {
return -1;
}
mutex_unlock(&locks[dev]);
return 0;
}
int spi_transfer_byte(spi_t dev, char out, char *in)
{
char tmp;
LPC_SSPx_Type *spi;
switch (dev) {
#if SPI_0_EN
case SPI_0:
spi = LPC_SSP0;
break;
#endif
#if SPI_1_EN
case SPI_1:
spi = LPC_SSP1;
break;
#endif
default:
return 0;
}
/* Wait while the BUSY flag is set */
while(spi->SR & (1 << 4)) {}
/* Put byte in the TX Fifo */
*((volatile uint8_t *)(&spi->DR)) = (uint8_t)out;
/* Wait until the current byte is transfered */
while(!(spi->SR & (1 << 2)) ) {}
/* Read the returned byte */
tmp = *((volatile uint8_t *)(&spi->DR));
/* 'return' response byte if wished for */
if (in) {
*in = tmp;
}
return 1;
}
void spi_transmission_begin(spi_t dev, char reset_val)
{
/* Slave mode not supported */
}
void spi_poweron(spi_t dev)
{
switch (dev) {
#if SPI_0_EN
case SPI_0:
/* De-assert SPI0 */
LPC_SYSCON->PRESETCTRL |= (1 << 0);
/* Enable SPI0 clock */
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 11);
/* Clock div : 48MHz */
LPC_SYSCON->SSP0CLKDIV = 1;
break;
#endif
#if SPI_1_EN
case SPI_1:
/* De-assert SPI1 */
LPC_SYSCON->PRESETCTRL |= (1 << 2);
/* Enable SPI1 clock */
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 18);
/* Clock div : 48MHz */
LPC_SYSCON->SSP1CLKDIV = 1;
break;
#endif
}
}
void spi_poweroff(spi_t dev)
{
switch (dev) {
#if SPI_0_EN
case SPI_0:
/* Assert SPI0 */
LPC_SYSCON->PRESETCTRL &= ~(1 << 0);
/* Disable SPI0 clock */
LPC_SYSCON->SYSAHBCLKCTRL &= ~(1 << 11);
break;
#endif
#if SPI_1_EN
case SPI_1:
/* Assert SPI1 */
LPC_SYSCON->PRESETCTRL &= ~(1 << 2);
/* Disable SPI1 clock */
LPC_SYSCON->SYSAHBCLKCTRL &= ~(1 << 18);
break;
#endif
}
}
#endif /* SPI_NUMOF */