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/*
* Copyright (C) 2014 Freie Universitรคt 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_nrf51822
* @{
*
* @file
* @brief Low-level SPI driver implementation
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
* @author Frank Holtz <frank-riot2015@holtznet.de>
*
* @}
*/
#include "cpu.h"
#include "mutex.h"
#include "periph/spi.h"
#include "periph_conf.h"
/* guard this file in case no SPI device is defined */
#if SPI_NUMOF
/* static port mapping */
static NRF_SPI_Type *const spi[] = {
#if SPI_0_EN
SPI_0_DEV,
#endif
#if SPI_1_EN
SPI_1_DEV
#endif
};
/**
* @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)
{
spi_poweron(dev);
/* disable the device -> nRF51822 reference 3.0 26.1.1 and 27.1*/
spi[dev]->ENABLE = 0;
switch(dev) {
#if SPI_0_EN
case SPI_0:
/* disable TWI Interface */
NRF_TWI0->ENABLE = 0;
break;
#endif
#if SPI_1_EN
case SPI_1:
/* disable SPI Slave */
NRF_SPIS1->ENABLE = 0;
/* disable TWI Interface */
NRF_TWI1->ENABLE = 0;
break;
#endif
default:
return -1;
}
/* configure direction of used pins */
spi_conf_pins(dev);
/* configure SPI mode */
switch (conf) {
case SPI_CONF_FIRST_RISING:
spi[dev]->CONFIG = (SPI_CONFIG_CPOL_ActiveHigh << 2) | (SPI_CONFIG_CPHA_Leading << 1);
break;
case SPI_CONF_SECOND_RISING:
spi[dev]->CONFIG = (SPI_CONFIG_CPOL_ActiveHigh << 2) | (SPI_CONFIG_CPHA_Trailing << 1);
break;
case SPI_CONF_FIRST_FALLING:
spi[dev]->CONFIG = (SPI_CONFIG_CPOL_ActiveLow << 2) | (SPI_CONFIG_CPHA_Leading << 1);
break;
case SPI_CONF_SECOND_FALLING:
spi[dev]->CONFIG = (SPI_CONFIG_CPOL_ActiveLow << 2) | (SPI_CONFIG_CPHA_Trailing << 1);
break;
}
/* select bus speed */
switch (speed) {
case SPI_SPEED_100KHZ: /* 125 KHz for this device */
spi[dev]->FREQUENCY = SPI_FREQUENCY_FREQUENCY_K125;
break;
case SPI_SPEED_400KHZ: /* 500 KHz for this device */
spi[dev]->FREQUENCY = SPI_FREQUENCY_FREQUENCY_K500;
break;
case SPI_SPEED_1MHZ: /* 1 MHz for this device */
spi[dev]->FREQUENCY = SPI_FREQUENCY_FREQUENCY_M1;
break;
case SPI_SPEED_5MHZ: /* 4 MHz for this device */
spi[dev]->FREQUENCY = SPI_FREQUENCY_FREQUENCY_M4;
break;
case SPI_SPEED_10MHZ: /* 8 MHz for this device */
spi[dev]->FREQUENCY = SPI_FREQUENCY_FREQUENCY_M8;
break;
}
/* finally enable the device */
spi[dev]->ENABLE = 1;
return 0;
}
int spi_init_slave(spi_t dev, spi_conf_t conf, char (*cb)(char data))
{
(void) dev;
(void) conf;
(void) cb;
/* This API is incompatible with nRF51 SPIS */
return -1;
}
int spi_conf_pins(spi_t dev)
{
switch (dev) {
#if SPI_0_EN
case SPI_0:
/* set pin direction */
NRF_GPIO->DIRSET = (1 << SPI_0_PIN_MOSI) | (1 << SPI_0_PIN_SCK);
NRF_GPIO->DIRCLR = (1 << SPI_0_PIN_MISO);
/* select pins to be used by SPI */
spi[dev]->PSELMOSI = SPI_0_PIN_MOSI;
spi[dev]->PSELMISO = SPI_0_PIN_MISO;
spi[dev]->PSELSCK = SPI_0_PIN_SCK;
break;
#endif
#if SPI_1_EN
case SPI_1:
/* set pin direction */
NRF_GPIO->DIRSET = (1 << SPI_1_PIN_MOSI) | (1 << SPI_1_PIN_SCK);
NRF_GPIO->DIRCLR = (1 << SPI_1_PIN_MISO);
/* select pins to be used by SPI */
spi[dev]->PSELMOSI = SPI_1_PIN_MOSI;
spi[dev]->PSELMISO = SPI_1_PIN_MISO;
spi[dev]->PSELSCK = SPI_1_PIN_SCK;
break;
#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)
{
return spi_transfer_bytes(dev, &out, in, 1);
}
int spi_transfer_bytes(spi_t dev, char *out, char *in, unsigned int length)
{
if ((unsigned int)dev >= SPI_NUMOF) {
return -1;
}
for (unsigned i = 0; i < length; i++) {
char tmp = (out) ? out[i] : 0;
spi[dev]->EVENTS_READY = 0;
spi[dev]->TXD = (uint8_t)tmp;
while (spi[dev]->EVENTS_READY != 1) {}
tmp = (char)spi[dev]->RXD;
if (in) {
in[i] = tmp;
}
}
return length;
}
int spi_transfer_reg(spi_t dev, uint8_t reg, char out, char *in)
{
spi_transfer_byte(dev, reg, 0);
return spi_transfer_byte(dev, out, in);
}
int spi_transfer_regs(spi_t dev, uint8_t reg, char *out, char *in, unsigned int length)
{
spi_transfer_byte(dev, reg, 0);
return spi_transfer_bytes(dev, out, in, length);
}
void spi_transmission_begin(spi_t dev, char reset_val)
{
(void) dev;
(void) reset_val;
/* spi slave is not implemented */
}
void spi_poweron(spi_t dev)
{
if ((unsigned int)dev < SPI_NUMOF) {
spi[dev]->POWER = 1;
}
}
void spi_poweroff(spi_t dev)
{
if ((unsigned int)dev < SPI_NUMOF) {
spi[dev]->POWER = 0;
}
}
#endif /* SPI_NUMOF */
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