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mbed-os/targets/TARGET_NORDIC/TARGET_MCU_NRF51822/spi_api.c

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/* mbed Microcontroller Library
* Copyright (c) 2013 Nordic Semiconductor
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
//#include <math.h>
#include "mbed_assert.h"
#include "spi_api.h"
#include "cmsis.h"
#include "pinmap.h"
#include "mbed_error.h"
#define SPIS_MESSAGE_SIZE 1
volatile uint8_t m_tx_buf[SPIS_MESSAGE_SIZE] = {0};
volatile uint8_t m_rx_buf[SPIS_MESSAGE_SIZE] = {0};
// nRF51822's I2C_0 and SPI_0 (I2C_1, SPI_1 and SPIS1) share the same address.
// They can't be used at the same time. So we use two global variable to track the usage.
// See nRF51822 address information at nRF51822_PS v2.0.pdf - Table 15 Peripheral instance reference
extern volatile i2c_spi_peripheral_t i2c0_spi0_peripheral; // from i2c_api.c
extern volatile i2c_spi_peripheral_t i2c1_spi1_peripheral;
void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel)
{
SPIName spi = SPI_0;
if (ssel == NC && i2c0_spi0_peripheral.usage == I2C_SPI_PERIPHERAL_FOR_SPI &&
i2c0_spi0_peripheral.sda_mosi == (uint8_t)mosi &&
i2c0_spi0_peripheral.scl_miso == (uint8_t)miso &&
i2c0_spi0_peripheral.sclk == (uint8_t)sclk) {
// The SPI with the same pins is already initialized
spi = SPI_0;
obj->peripheral = 0x1;
} else if (ssel == NC && i2c1_spi1_peripheral.usage == I2C_SPI_PERIPHERAL_FOR_SPI &&
i2c1_spi1_peripheral.sda_mosi == (uint8_t)mosi &&
i2c1_spi1_peripheral.scl_miso == (uint8_t)miso &&
i2c1_spi1_peripheral.sclk == (uint8_t)sclk) {
// The SPI with the same pins is already initialized
spi = SPI_1;
obj->peripheral = 0x2;
} else if (i2c1_spi1_peripheral.usage == 0) {
i2c1_spi1_peripheral.usage = I2C_SPI_PERIPHERAL_FOR_SPI;
i2c1_spi1_peripheral.sda_mosi = (uint8_t)mosi;
i2c1_spi1_peripheral.scl_miso = (uint8_t)miso;
i2c1_spi1_peripheral.sclk = (uint8_t)sclk;
spi = SPI_1;
obj->peripheral = 0x2;
} else if (i2c0_spi0_peripheral.usage == 0) {
i2c0_spi0_peripheral.usage = I2C_SPI_PERIPHERAL_FOR_SPI;
i2c0_spi0_peripheral.sda_mosi = (uint8_t)mosi;
i2c0_spi0_peripheral.scl_miso = (uint8_t)miso;
i2c0_spi0_peripheral.sclk = (uint8_t)sclk;
spi = SPI_0;
obj->peripheral = 0x1;
} else {
// No available peripheral
error("No available SPI");
}
if (ssel==NC) {
obj->spi = (NRF_SPI_Type *)spi;
obj->spis = (NRF_SPIS_Type *)NC;
} else {
obj->spi = (NRF_SPI_Type *)NC;
obj->spis = (NRF_SPIS_Type *)spi;
}
// pin out the spi pins
if (ssel != NC) { //slave
obj->spis->POWER = 0;
obj->spis->POWER = 1;
NRF_GPIO->PIN_CNF[mosi] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)
| (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos)
| (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos)
| (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);
NRF_GPIO->PIN_CNF[miso] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)
| (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos)
| (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos)
| (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);
NRF_GPIO->PIN_CNF[sclk] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)
| (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos)
| (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos)
| (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);
NRF_GPIO->PIN_CNF[ssel] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)
| (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos)
| (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos)
| (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);
obj->spis->PSELMOSI = mosi;
obj->spis->PSELMISO = miso;
obj->spis->PSELSCK = sclk;
obj->spis->PSELCSN = ssel;
obj->spis->EVENTS_END = 0;
obj->spis->EVENTS_ACQUIRED = 0;
obj->spis->MAXRX = SPIS_MESSAGE_SIZE;
obj->spis->MAXTX = SPIS_MESSAGE_SIZE;
obj->spis->TXDPTR = (uint32_t)&m_tx_buf[0];
obj->spis->RXDPTR = (uint32_t)&m_rx_buf[0];
obj->spis->SHORTS = (SPIS_SHORTS_END_ACQUIRE_Enabled << SPIS_SHORTS_END_ACQUIRE_Pos);
spi_format(obj, 8, 0, 1); // 8 bits, mode 0, slave
} else { //master
obj->spi->POWER = 0;
obj->spi->POWER = 1;
//NRF_GPIO->DIR |= (1<<mosi);
NRF_GPIO->PIN_CNF[mosi] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)
| (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos)
| (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos)
| (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos);
obj->spi->PSELMOSI = mosi;
NRF_GPIO->PIN_CNF[sclk] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)
| (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos)
| (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos)
| (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos);
obj->spi->PSELSCK = sclk;
//NRF_GPIO->DIR &= ~(1<<miso);
NRF_GPIO->PIN_CNF[miso] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)
| (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos)
| (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos)
| (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);
obj->spi->PSELMISO = miso;
obj->spi->EVENTS_READY = 0U;
spi_format(obj, 8, 0, 0); // 8 bits, mode 0, master
spi_frequency(obj, 1000000);
}
}
void spi_free(spi_t *obj)
{
}
static inline void spi_disable(spi_t *obj, int slave)
{
if (slave) {
obj->spis->ENABLE = (SPIS_ENABLE_ENABLE_Disabled << SPIS_ENABLE_ENABLE_Pos);
} else {
obj->spi->ENABLE = (SPI_ENABLE_ENABLE_Disabled << SPI_ENABLE_ENABLE_Pos);
}
}
static inline void spi_enable(spi_t *obj, int slave)
{
if (slave) {
obj->spis->ENABLE = (SPIS_ENABLE_ENABLE_Enabled << SPIS_ENABLE_ENABLE_Pos);
} else {
obj->spi->ENABLE = (SPI_ENABLE_ENABLE_Enabled << SPI_ENABLE_ENABLE_Pos);
}
}
void spi_format(spi_t *obj, int bits, int mode, int slave)
{
uint32_t config_mode = 0;
spi_disable(obj, slave);
if (bits != 8) {
error("Only 8bits SPI supported");
}
switch (mode) {
case 0:
config_mode = (SPI_CONFIG_CPHA_Leading << SPI_CONFIG_CPHA_Pos) | (SPI_CONFIG_CPOL_ActiveHigh << SPI_CONFIG_CPOL_Pos);
break;
case 1:
config_mode = (SPI_CONFIG_CPHA_Trailing << SPI_CONFIG_CPHA_Pos) | (SPI_CONFIG_CPOL_ActiveHigh << SPI_CONFIG_CPOL_Pos);
break;
case 2:
config_mode = (SPI_CONFIG_CPHA_Leading << SPI_CONFIG_CPHA_Pos) | (SPI_CONFIG_CPOL_ActiveLow << SPI_CONFIG_CPOL_Pos);
break;
case 3:
config_mode = (SPI_CONFIG_CPHA_Trailing << SPI_CONFIG_CPHA_Pos) | (SPI_CONFIG_CPOL_ActiveLow << SPI_CONFIG_CPOL_Pos);
break;
default:
error("SPI format error");
break;
}
//default to msb first
if (slave) {
obj->spis->CONFIG = (config_mode | (SPI_CONFIG_ORDER_MsbFirst << SPI_CONFIG_ORDER_Pos));
} else {
obj->spi->CONFIG = (config_mode | (SPI_CONFIG_ORDER_MsbFirst << SPI_CONFIG_ORDER_Pos));
}
spi_enable(obj, slave);
}
void spi_frequency(spi_t *obj, int hz)
{
if ((int)obj->spi==NC) {
return;
}
spi_disable(obj, 0);
if (hz<250000) { //125Kbps
obj->spi->FREQUENCY = (uint32_t) SPI_FREQUENCY_FREQUENCY_K125;
} else if (hz<500000) { //250Kbps
obj->spi->FREQUENCY = (uint32_t) SPI_FREQUENCY_FREQUENCY_K250;
} else if (hz<1000000) { //500Kbps
obj->spi->FREQUENCY = (uint32_t) SPI_FREQUENCY_FREQUENCY_K500;
} else if (hz<2000000) { //1Mbps
obj->spi->FREQUENCY = (uint32_t) SPI_FREQUENCY_FREQUENCY_M1;
} else if (hz<4000000) { //2Mbps
obj->spi->FREQUENCY = (uint32_t) SPI_FREQUENCY_FREQUENCY_M2;
} else if (hz<8000000) { //4Mbps
obj->spi->FREQUENCY = (uint32_t) SPI_FREQUENCY_FREQUENCY_M4;
} else { //8Mbps
obj->spi->FREQUENCY = (uint32_t) SPI_FREQUENCY_FREQUENCY_M8;
}
spi_enable(obj, 0);
}
static inline int spi_readable(spi_t *obj)
{
return (obj->spi->EVENTS_READY == 1);
}
static inline int spi_writeable(spi_t *obj)
{
return (obj->spi->EVENTS_READY == 0);
}
static inline int spi_read(spi_t *obj)
{
while (!spi_readable(obj)) {
}
obj->spi->EVENTS_READY = 0;
return (int)obj->spi->RXD;
}
int spi_master_write(spi_t *obj, int value)
{
while (!spi_writeable(obj)) {
}
obj->spi->TXD = (uint32_t)value;
return spi_read(obj);
}
//static inline int spis_writeable(spi_t *obj) {
// return (obj->spis->EVENTS_ACQUIRED==1);
//}
int spi_slave_receive(spi_t *obj)
{
return obj->spis->EVENTS_END;
}
int spi_slave_read(spi_t *obj)
{
return m_rx_buf[0];
}
void spi_slave_write(spi_t *obj, int value)
{
m_tx_buf[0] = value & 0xFF;
obj->spis->TASKS_RELEASE = 1;
obj->spis->EVENTS_ACQUIRED = 0;
obj->spis->EVENTS_END = 0;
}
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