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/*******************************************************************************
* Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved.
*
* 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 MAXIM INTEGRATED 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.
*
* Except as contained in this notice, the name of Maxim Integrated
* Products, Inc. shall not be used except as stated in the Maxim Integrated
* Products, Inc. Branding Policy.
*
* The mere transfer of this software does not imply any licenses
* of trade secrets, proprietary technology, copyrights, patents,
* trademarks, maskwork rights, or any other form of intellectual
* property whatsoever. Maxim Integrated Products, Inc. retains all
* ownership rights.
*******************************************************************************
*/
#include <string.h>
#include "mbed_assert.h"
#include "cmsis.h"
#include "spi_api.h"
#include "pinmap.h"
#include "ioman_regs.h"
#include "clkman_regs.h"
#include "PeripheralPins.h"
#define DEFAULT_CHAR 8
#define DEFAULT_MODE 0
#define DEFAULT_FREQ 1000000
// Formatting settings
static int spi_bits;
//******************************************************************************
void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel)
{
// Make sure pins are pointing to the same SPI instance
SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
SPIName spi_cntl;
// Give the application the option to manually control Slave Select
if((SPIName)spi_ssel != (SPIName)NC) {
spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
} else {
spi_cntl = spi_sclk;
}
SPIName spi = (SPIName)pinmap_merge(spi_data, spi_cntl);
MBED_ASSERT((SPIName)spi != (SPIName)NC);
// Set the obj pointer to the proper SPI Instance
obj->spi = (mxc_spi_regs_t*)spi;
// Set the SPI index and FIFOs
obj->index = MXC_SPI_BASE_TO_INSTANCE(obj->spi);
obj->rxfifo = MXC_SPI_GET_RXFIFO(obj->index);
obj->txfifo = MXC_SPI_GET_TXFIFO(obj->index);
// Configure the pins
pinmap_pinout(mosi, PinMap_SPI_MOSI);
pinmap_pinout(miso, PinMap_SPI_MISO);
pinmap_pinout(sclk, PinMap_SPI_SCLK);
pinmap_pinout(ssel, PinMap_SPI_SSEL);
// Enable SPI and FIFOs
obj->spi->gen_ctrl = (MXC_F_SPI_GEN_CTRL_SPI_MSTR_EN |
MXC_F_SPI_GEN_CTRL_TX_FIFO_EN |
MXC_F_SPI_GEN_CTRL_RX_FIFO_EN );
// Give instance the default settings
spi_format(obj, DEFAULT_CHAR, DEFAULT_MODE, 0);
spi_frequency(obj, DEFAULT_FREQ);
}
//******************************************************************************
void spi_format(spi_t *obj, int bits, int mode, int slave)
{
// Check the validity of the inputs
MBED_ASSERT(((bits >= 1) && (bits <= 32)) && ((mode >= 0) && (mode <= 3)));
// Only supports master mode
MBED_ASSERT(!slave);
// Save formatting data
spi_bits = bits;
// Set the mode
obj->spi->mstr_cfg &= ~(MXC_F_SPI_MSTR_CFG_SPI_MODE);
obj->spi->mstr_cfg |= (mode << MXC_F_SPI_MSTR_CFG_SPI_MODE_POS);
}
//******************************************************************************
void spi_frequency(spi_t *obj, int hz)
{
// Maximum frequency is half the system frequency
MBED_ASSERT((unsigned int)hz < (SystemCoreClock / 2));
unsigned clocks = ((SystemCoreClock/2)/(hz));
// Figure out the divider ratio
int clk_div = 1;
while(clk_div < 10) {
if(clocks < 0x10) {
break;
}
clk_div++;
clocks = clocks >> 1;
}
// Turn on the SPI clock
if(obj->index == 0) {
MXC_CLKMAN->clk_ctrl_3_spi0 = clk_div;
} else if(obj->index == 1) {
MXC_CLKMAN->clk_ctrl_4_spi1 = clk_div;
} else if(obj->index == 2) {
MXC_CLKMAN->clk_ctrl_5_spi2 = clk_div;
} else {
MBED_ASSERT(0);
}
// Set the number of clocks to hold sclk high and low
MXC_SET_FIELD(&obj->spi->mstr_cfg, (MXC_F_SPI_MSTR_CFG_SCK_HI_CLK | MXC_F_SPI_MSTR_CFG_SCK_LO_CLK),
((clocks << MXC_F_SPI_MSTR_CFG_SCK_HI_CLK_POS) | (clocks << MXC_F_SPI_MSTR_CFG_SCK_LO_CLK_POS)));
}
//******************************************************************************
int spi_master_write(spi_t *obj, int value)
{
int bits = spi_bits;
if(spi_bits == 32) {
bits = 0;
}
// Create the header
uint16_t header = ((0x3 << MXC_F_SPI_FIFO_DIR_POS ) | // TX and RX
(0x0 << MXC_F_SPI_FIFO_UNIT_POS) | // Send bits
(bits << MXC_F_SPI_FIFO_SIZE_POS) | // Number of units
(0x1 << MXC_F_SPI_FIFO_DASS_POS)); // Deassert SS
// Send the message header
obj->txfifo->txfifo_16 = header;
// Send the data
if(spi_bits < 17) {
obj->txfifo->txfifo_16 = (uint16_t)value;
} else {
obj->txfifo->txfifo_32 = (uint32_t)value;
}
// Get the data
bits = spi_bits;
int result = 0;
int i = 0;
while(bits > 0) {
// Wait for data
while(((obj->spi->fifo_ctrl & MXC_F_SPI_FIFO_CTRL_RX_FIFO_USED)
>> MXC_F_SPI_FIFO_CTRL_RX_FIFO_USED_POS) < 1) {}
result |= (obj->rxfifo->rxfifo_8 << (i++*8));
bits-=8;
}
return result;
}
//******************************************************************************
int spi_busy(spi_t *obj)
{
return !(obj->spi->intfl & MXC_F_SPI_INTFL_TX_READY);
}
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