tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Maxim/TARGET_MAX32610/spi_api.c

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  33
  34 #include <string.h>
  35 #include "mbed_assert.h"
  36 #include "cmsis.h"
  37 #include "spi_api.h"
  38 #include "pinmap.h"
  39 #include "ioman_regs.h"
  40 #include "clkman_regs.h"
  41 #include "PeripheralPins.h"
  42
  43 #define DEFAULT_CHAR    8
  44 #define DEFAULT_MODE    0
  45 #define DEFAULT_FREQ    1000000
  46
  47 // Formatting settings
  48 static int spi_bits;
  49
  50 //******************************************************************************
  51 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel)
  52 {
  53     // Make sure pins are pointing to the same SPI instance
  54     SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
  55     SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
  56     SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
  57     SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
  58
  59     SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
  60     SPIName spi_cntl;
  61
  62     // Give the application the option to manually control Slave Select
  63     if((SPIName)spi_ssel != (SPIName)NC) {
  64         spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
  65     } else {
  66         spi_cntl = spi_sclk;
  67     }
  68
  69     SPIName spi = (SPIName)pinmap_merge(spi_data, spi_cntl);
  70
  71     MBED_ASSERT((SPIName)spi != (SPIName)NC);
  72
  73     // Set the obj pointer to the proper SPI Instance
  74     obj->spi = (mxc_spi_regs_t*)spi;
  75
  76     // Set the SPI index and FIFOs
  77     obj->index = MXC_SPI_BASE_TO_INSTANCE(obj->spi);
  78     obj->rxfifo = MXC_SPI_GET_RXFIFO(obj->index);
  79     obj->txfifo = MXC_SPI_GET_TXFIFO(obj->index);
  80
  81     // Configure the pins
  82     pinmap_pinout(mosi, PinMap_SPI_MOSI);
  83     pinmap_pinout(miso, PinMap_SPI_MISO);
  84     pinmap_pinout(sclk, PinMap_SPI_SCLK);
  85     pinmap_pinout(ssel, PinMap_SPI_SSEL);
  86
  87     // Enable SPI and FIFOs
  88     obj->spi->gen_ctrl = (MXC_F_SPI_GEN_CTRL_SPI_MSTR_EN |
  89                           MXC_F_SPI_GEN_CTRL_TX_FIFO_EN |
  90                           MXC_F_SPI_GEN_CTRL_RX_FIFO_EN );
  91
  92     // Give instance the default settings
  93     spi_format(obj, DEFAULT_CHAR, DEFAULT_MODE, 0);
  94     spi_frequency(obj, DEFAULT_FREQ);
  95 }
  96
  97 //******************************************************************************
  98 void spi_format(spi_t *obj, int bits, int mode, int slave)
  99 {
 100     // Check the validity of the inputs
 101     MBED_ASSERT(((bits >= 1) && (bits <= 32)) && ((mode >= 0) && (mode <= 3)));
 102
 103     // Only supports master mode
 104     MBED_ASSERT(!slave);
 105
 106     // Save formatting data
 107     spi_bits = bits;
 108
 109     // Set the mode
 110     obj->spi->mstr_cfg &= ~(MXC_F_SPI_MSTR_CFG_SPI_MODE);
 111     obj->spi->mstr_cfg |= (mode << MXC_F_SPI_MSTR_CFG_SPI_MODE_POS);
 112 }
 113
 114 //******************************************************************************
 115 void spi_frequency(spi_t *obj, int hz)
 116 {
 117     // Maximum frequency is half the system frequency
 118     MBED_ASSERT((unsigned int)hz < (SystemCoreClock / 2));
 119     unsigned clocks = ((SystemCoreClock/2)/(hz));
 120
 121     // Figure out the divider ratio
 122     int clk_div = 1;
 123     while(clk_div < 10) {
 124         if(clocks < 0x10) {
 125             break;
 126         }
 127         clk_div++;
 128         clocks = clocks >> 1;
 129     }
 130
 131     // Turn on the SPI clock
 132     if(obj->index == 0) {
 133         MXC_CLKMAN->clk_ctrl_3_spi0 = clk_div;
 134     } else if(obj->index == 1) {
 135         MXC_CLKMAN->clk_ctrl_4_spi1 = clk_div;
 136     } else if(obj->index == 2) {
 137         MXC_CLKMAN->clk_ctrl_5_spi2 = clk_div;
 138     } else {
 139         MBED_ASSERT(0);
 140     }
 141
 142     // Set the number of clocks to hold sclk high and low
 143     MXC_SET_FIELD(&obj->spi->mstr_cfg, (MXC_F_SPI_MSTR_CFG_SCK_HI_CLK | MXC_F_SPI_MSTR_CFG_SCK_LO_CLK),
 144         ((clocks << MXC_F_SPI_MSTR_CFG_SCK_HI_CLK_POS) | (clocks << MXC_F_SPI_MSTR_CFG_SCK_LO_CLK_POS)));
 145 }
 146
 147 //******************************************************************************
 148 int  spi_master_write(spi_t *obj, int value)
 149 {
 150     int bits = spi_bits;
 151     if(spi_bits == 32) {
 152         bits = 0;
 153     }
 154     // Create the header
 155     uint16_t header = ((0x3 << MXC_F_SPI_FIFO_DIR_POS ) |  // TX and RX
 156                        (0x0 << MXC_F_SPI_FIFO_UNIT_POS) | // Send bits
 157                        (bits << MXC_F_SPI_FIFO_SIZE_POS) | // Number of units
 158                        (0x1 << MXC_F_SPI_FIFO_DASS_POS));      // Deassert SS
 159
 160     // Send the message header
 161     obj->txfifo->txfifo_16 = header;
 162
 163     // Send the data
 164     if(spi_bits < 17) {
 165         obj->txfifo->txfifo_16 = (uint16_t)value;
 166     } else {
 167         obj->txfifo->txfifo_32 = (uint32_t)value;
 168     }
 169
 170     // Get the data
 171     bits = spi_bits;
 172     int result = 0;
 173     int i = 0;
 174     while(bits > 0) {
 175         // Wait for data
 176         while(((obj->spi->fifo_ctrl & MXC_F_SPI_FIFO_CTRL_RX_FIFO_USED)
 177                 >> MXC_F_SPI_FIFO_CTRL_RX_FIFO_USED_POS) < 1) {}
 178
 179         result |= (obj->rxfifo->rxfifo_8 << (i++*8));
 180         bits-=8;
 181     }
 182
 183     return result;
 184 }
 185
 186 //******************************************************************************
 187 int  spi_busy(spi_t *obj)
 188 {
 189     return !(obj->spi->intfl & MXC_F_SPI_INTFL_TX_READY);
 190 }