Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

targets/TARGET_Maxim/TARGET_MAX32600/spi_api.c@0:f269e3021894, 2016-10-23 (annotated)

Committer:
elessair
Date:
Sun Oct 23 15:10:02 2016 +0000
Revision:
0:f269e3021894
Initial commit

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elessair 0:f269e3021894 1 /*******************************************************************************
elessair 0:f269e3021894 2 * Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved.
elessair 0:f269e3021894 3 *
elessair 0:f269e3021894 4 * Permission is hereby granted, free of charge, to any person obtaining a
elessair 0:f269e3021894 5 * copy of this software and associated documentation files (the "Software"),
elessair 0:f269e3021894 6 * to deal in the Software without restriction, including without limitation
elessair 0:f269e3021894 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
elessair 0:f269e3021894 8 * and/or sell copies of the Software, and to permit persons to whom the
elessair 0:f269e3021894 9 * Software is furnished to do so, subject to the following conditions:
elessair 0:f269e3021894 10 *
elessair 0:f269e3021894 11 * The above copyright notice and this permission notice shall be included
elessair 0:f269e3021894 12 * in all copies or substantial portions of the Software.
elessair 0:f269e3021894 13 *
elessair 0:f269e3021894 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
elessair 0:f269e3021894 15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
elessair 0:f269e3021894 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
elessair 0:f269e3021894 17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
elessair 0:f269e3021894 18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
elessair 0:f269e3021894 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
elessair 0:f269e3021894 20 * OTHER DEALINGS IN THE SOFTWARE.
elessair 0:f269e3021894 21 *
elessair 0:f269e3021894 22 * Except as contained in this notice, the name of Maxim Integrated
elessair 0:f269e3021894 23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
elessair 0:f269e3021894 24 * Products, Inc. Branding Policy.
elessair 0:f269e3021894 25 *
elessair 0:f269e3021894 26 * The mere transfer of this software does not imply any licenses
elessair 0:f269e3021894 27 * of trade secrets, proprietary technology, copyrights, patents,
elessair 0:f269e3021894 28 * trademarks, maskwork rights, or any other form of intellectual
elessair 0:f269e3021894 29 * property whatsoever. Maxim Integrated Products, Inc. retains all
elessair 0:f269e3021894 30 * ownership rights.
elessair 0:f269e3021894 31 *******************************************************************************
elessair 0:f269e3021894 32 */
elessair 0:f269e3021894 33
elessair 0:f269e3021894 34 #include <string.h>
elessair 0:f269e3021894 35 #include "mbed_assert.h"
elessair 0:f269e3021894 36 #include "cmsis.h"
elessair 0:f269e3021894 37 #include "spi_api.h"
elessair 0:f269e3021894 38 #include "pinmap.h"
elessair 0:f269e3021894 39 #include "ioman_regs.h"
elessair 0:f269e3021894 40 #include "clkman_regs.h"
elessair 0:f269e3021894 41 #include "PeripheralPins.h"
elessair 0:f269e3021894 42
elessair 0:f269e3021894 43 #define DEFAULT_CHAR 8
elessair 0:f269e3021894 44 #define DEFAULT_MODE 0
elessair 0:f269e3021894 45 #define DEFAULT_FREQ 1000000
elessair 0:f269e3021894 46
elessair 0:f269e3021894 47 // Formatting settings
elessair 0:f269e3021894 48 static int spi_bits;
elessair 0:f269e3021894 49
elessair 0:f269e3021894 50 //******************************************************************************
elessair 0:f269e3021894 51 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel)
elessair 0:f269e3021894 52 {
elessair 0:f269e3021894 53 // Make sure pins are pointing to the same SPI instance
elessair 0:f269e3021894 54 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
elessair 0:f269e3021894 55 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
elessair 0:f269e3021894 56 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
elessair 0:f269e3021894 57 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
elessair 0:f269e3021894 58
elessair 0:f269e3021894 59 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
elessair 0:f269e3021894 60 SPIName spi_cntl;
elessair 0:f269e3021894 61
elessair 0:f269e3021894 62 // Give the application the option to manually control Slave Select
elessair 0:f269e3021894 63 if((SPIName)spi_ssel != (SPIName)NC) {
elessair 0:f269e3021894 64 spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
elessair 0:f269e3021894 65 } else {
elessair 0:f269e3021894 66 spi_cntl = spi_sclk;
elessair 0:f269e3021894 67 }
elessair 0:f269e3021894 68
elessair 0:f269e3021894 69 SPIName spi = (SPIName)pinmap_merge(spi_data, spi_cntl);
elessair 0:f269e3021894 70
elessair 0:f269e3021894 71 MBED_ASSERT((SPIName)spi != (SPIName)NC);
elessair 0:f269e3021894 72
elessair 0:f269e3021894 73 // Set the obj pointer to the proper SPI Instance
elessair 0:f269e3021894 74 obj->spi = (mxc_spi_regs_t*)spi;
elessair 0:f269e3021894 75
elessair 0:f269e3021894 76 // Set the SPI index and FIFOs
elessair 0:f269e3021894 77 obj->index = MXC_SPI_BASE_TO_INSTANCE(obj->spi);
elessair 0:f269e3021894 78 obj->rxfifo = MXC_SPI_GET_RXFIFO(obj->index);
elessair 0:f269e3021894 79 obj->txfifo = MXC_SPI_GET_TXFIFO(obj->index);
elessair 0:f269e3021894 80
elessair 0:f269e3021894 81 // Configure the pins
elessair 0:f269e3021894 82 pinmap_pinout(mosi, PinMap_SPI_MOSI);
elessair 0:f269e3021894 83 pinmap_pinout(miso, PinMap_SPI_MISO);
elessair 0:f269e3021894 84 pinmap_pinout(sclk, PinMap_SPI_SCLK);
elessair 0:f269e3021894 85 pinmap_pinout(ssel, PinMap_SPI_SSEL);
elessair 0:f269e3021894 86
elessair 0:f269e3021894 87 // Enable SPI and FIFOs
elessair 0:f269e3021894 88 obj->spi->gen_ctrl = (MXC_F_SPI_GEN_CTRL_SPI_MSTR_EN |
elessair 0:f269e3021894 89 MXC_F_SPI_GEN_CTRL_TX_FIFO_EN |
elessair 0:f269e3021894 90 MXC_F_SPI_GEN_CTRL_RX_FIFO_EN );
elessair 0:f269e3021894 91 }
elessair 0:f269e3021894 92
elessair 0:f269e3021894 93 //******************************************************************************
elessair 0:f269e3021894 94 void spi_format(spi_t *obj, int bits, int mode, int slave)
elessair 0:f269e3021894 95 {
elessair 0:f269e3021894 96 // Check the validity of the inputs
elessair 0:f269e3021894 97 MBED_ASSERT(((bits >= 1) && (bits <= 32)) && ((mode >= 0) && (mode <= 3)));
elessair 0:f269e3021894 98
elessair 0:f269e3021894 99 // Only supports master mode
elessair 0:f269e3021894 100 MBED_ASSERT(!slave);
elessair 0:f269e3021894 101
elessair 0:f269e3021894 102 // Save formatting data
elessair 0:f269e3021894 103 spi_bits = bits;
elessair 0:f269e3021894 104
elessair 0:f269e3021894 105 // Set the mode
elessair 0:f269e3021894 106 obj->spi->mstr_cfg &= ~(MXC_F_SPI_MSTR_CFG_SPI_MODE);
elessair 0:f269e3021894 107 obj->spi->mstr_cfg |= (mode << MXC_F_SPI_MSTR_CFG_SPI_MODE_POS);
elessair 0:f269e3021894 108 }
elessair 0:f269e3021894 109
elessair 0:f269e3021894 110 //******************************************************************************
elessair 0:f269e3021894 111 void spi_frequency(spi_t *obj, int hz)
elessair 0:f269e3021894 112 {
elessair 0:f269e3021894 113 // Maximum frequency is half the system frequency
elessair 0:f269e3021894 114 MBED_ASSERT((unsigned int)hz <= (SystemCoreClock / 2));
elessair 0:f269e3021894 115 unsigned clocks = ((SystemCoreClock/2)/(hz));
elessair 0:f269e3021894 116
elessair 0:f269e3021894 117 // Figure out the divider ratio
elessair 0:f269e3021894 118 int clk_div = 1;
elessair 0:f269e3021894 119 while(clk_div < 10) {
elessair 0:f269e3021894 120 if(clocks < 0x10) {
elessair 0:f269e3021894 121 break;
elessair 0:f269e3021894 122 }
elessair 0:f269e3021894 123 clk_div++;
elessair 0:f269e3021894 124 clocks = clocks >> 1;
elessair 0:f269e3021894 125 }
elessair 0:f269e3021894 126
elessair 0:f269e3021894 127 // Turn on the SPI clock
elessair 0:f269e3021894 128 if(obj->index == 0) {
elessair 0:f269e3021894 129 MXC_CLKMAN->clk_ctrl_3_spi0 = clk_div;
elessair 0:f269e3021894 130 } else if(obj->index == 1) {
elessair 0:f269e3021894 131 MXC_CLKMAN->clk_ctrl_4_spi1 = clk_div;
elessair 0:f269e3021894 132 } else if(obj->index == 2) {
elessair 0:f269e3021894 133 MXC_CLKMAN->clk_ctrl_5_spi2 = clk_div;
elessair 0:f269e3021894 134 } else {
elessair 0:f269e3021894 135 MBED_ASSERT(0);
elessair 0:f269e3021894 136 }
elessair 0:f269e3021894 137
elessair 0:f269e3021894 138 // Set the number of clocks to hold sclk high and low
elessair 0:f269e3021894 139 MXC_SET_FIELD(&obj->spi->mstr_cfg, (MXC_F_SPI_MSTR_CFG_SCK_HI_CLK | MXC_F_SPI_MSTR_CFG_SCK_LO_CLK),
elessair 0:f269e3021894 140 ((clocks << MXC_F_SPI_MSTR_CFG_SCK_HI_CLK_POS) | (clocks << MXC_F_SPI_MSTR_CFG_SCK_LO_CLK_POS)));
elessair 0:f269e3021894 141 }
elessair 0:f269e3021894 142
elessair 0:f269e3021894 143 //******************************************************************************
elessair 0:f269e3021894 144 int spi_master_write(spi_t *obj, int value)
elessair 0:f269e3021894 145 {
elessair 0:f269e3021894 146 int bits = spi_bits;
elessair 0:f269e3021894 147 if(spi_bits == 32) {
elessair 0:f269e3021894 148 bits = 0;
elessair 0:f269e3021894 149 }
elessair 0:f269e3021894 150 // Create the header
elessair 0:f269e3021894 151 uint16_t header = ((0x3 << MXC_F_SPI_FIFO_DIR_POS ) | // TX and RX
elessair 0:f269e3021894 152 (0x0 << MXC_F_SPI_FIFO_UNIT_POS) | // Send bits
elessair 0:f269e3021894 153 (bits << MXC_F_SPI_FIFO_SIZE_POS) | // Number of units
elessair 0:f269e3021894 154 (0x1 << MXC_F_SPI_FIFO_DASS_POS)); // Deassert SS
elessair 0:f269e3021894 155
elessair 0:f269e3021894 156 // Send the message header
elessair 0:f269e3021894 157 obj->txfifo->txfifo_16 = header;
elessair 0:f269e3021894 158
elessair 0:f269e3021894 159 // Send the data
elessair 0:f269e3021894 160 if(spi_bits < 17) {
elessair 0:f269e3021894 161 obj->txfifo->txfifo_16 = (uint16_t)value;
elessair 0:f269e3021894 162 } else {
elessair 0:f269e3021894 163 obj->txfifo->txfifo_32 = (uint32_t)value;
elessair 0:f269e3021894 164 }
elessair 0:f269e3021894 165
elessair 0:f269e3021894 166 // Get the data
elessair 0:f269e3021894 167 bits = spi_bits;
elessair 0:f269e3021894 168 int result = 0;
elessair 0:f269e3021894 169 int i = 0;
elessair 0:f269e3021894 170 while(bits > 0) {
elessair 0:f269e3021894 171 // Wait for data
elessair 0:f269e3021894 172 while(((obj->spi->fifo_ctrl & MXC_F_SPI_FIFO_CTRL_RX_FIFO_USED)
elessair 0:f269e3021894 173 >> MXC_F_SPI_FIFO_CTRL_RX_FIFO_USED_POS) < 1) {}
elessair 0:f269e3021894 174
elessair 0:f269e3021894 175 result |= (obj->rxfifo->rxfifo_8 << (i++*8));
elessair 0:f269e3021894 176 bits-=8;
elessair 0:f269e3021894 177 }
elessair 0:f269e3021894 178
elessair 0:f269e3021894 179 return result;
elessair 0:f269e3021894 180 }
elessair 0:f269e3021894 181
elessair 0:f269e3021894 182 //******************************************************************************
elessair 0:f269e3021894 183 int spi_busy(spi_t *obj)
elessair 0:f269e3021894 184 {
elessair 0:f269e3021894 185 return !(obj->spi->intfl & MXC_F_SPI_INTFL_TX_READY);
elessair 0:f269e3021894 186 }