tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_Freescale/TARGET_KLXX/TARGET_KL43Z/spi_api.c

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include "mbed_assert.h"
  17 #include "spi_api.h"
  18
  19 #include <math.h>
  20
  21 #include "cmsis.h"
  22 #include "pinmap.h"
  23
  24 static const PinMap PinMap_SPI_SCLK[] = {
  25     {PTC3,  SPI_1, 2},
  26     {PTC5,  SPI_0, 2},
  27     {PTD1,  SPI_0, 2},
  28     {PTD5,  SPI_1, 2},
  29     {NC  ,  NC   , 0}
  30 };
  31
  32 static const PinMap PinMap_SPI_MOSI[] = {
  33     {PTB16, SPI_1, 2},
  34     {PTB17, SPI_1, 5},
  35     {PTC6,  SPI_0, 2},
  36     {PTC7,  SPI_0, 5},
  37     {PTD2,  SPI_0, 2},
  38     {PTD3,  SPI_0, 5},
  39     {PTD6,  SPI_1, 2},
  40     {PTD7,  SPI_1, 5},
  41     {PTE1,  SPI_1, 2},
  42     {NC  ,  NC   , 0}
  43 };
  44
  45 static const PinMap PinMap_SPI_MISO[] = {
  46     {PTB16, SPI_1, 5},
  47     {PTB17, SPI_1, 2},
  48     {PTC6,  SPI_0, 5},
  49     {PTC7,  SPI_0, 2},
  50     {PTD2,  SPI_0, 5},
  51     {PTD3,  SPI_0, 2},
  52     {PTD6,  SPI_1, 5},
  53     {PTD7,  SPI_1, 2},
  54     {PTE0,  SPI_1, 2},
  55     {PTE1,  SPI_1, 5},
  56     {NC   , NC   , 0}
  57 };
  58
  59 static const PinMap PinMap_SPI_SSEL[] = {
  60     {PTC4,  SPI_0, 2},
  61     {PTD0,  SPI_0, 2},
  62     {PTD4,  SPI_1, 2},
  63     {NC  ,  NC   , 0}
  64 };
  65
  66 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
  67     // determine the SPI to use
  68     SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
  69     SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
  70     SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
  71     SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
  72     SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
  73     SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
  74
  75     obj->spi = (SPI_Type*)pinmap_merge(spi_data, spi_cntl);
  76     MBED_ASSERT((int)obj->spi != NC);
  77
  78     // enable power and clocking
  79     switch ((int)obj->spi) {
  80         case SPI_0: SIM->SCGC5 |= 1 << 13; SIM->SCGC4 |= 1 << 22; break;
  81         case SPI_1: SIM->SCGC5 |= 1 << 13; SIM->SCGC4 |= 1 << 23; break;
  82     }
  83
  84     // set default format and frequency
  85     if (ssel == NC) {
  86         spi_format(obj, 8, 0, 0);  // 8 bits, mode 0, master
  87     } else {
  88         spi_format(obj, 8, 0, 1);  // 8 bits, mode 0, slave
  89     }
  90     spi_frequency(obj, 1000000);
  91
  92     // enable SPI
  93     obj->spi->C1 |= SPI_C1_SPE_MASK;
  94     obj->spi->C2 &= ~SPI_C2_SPIMODE_MASK; //8bit
  95
  96     // pin out the spi pins
  97     pinmap_pinout(mosi, PinMap_SPI_MOSI);
  98     pinmap_pinout(miso, PinMap_SPI_MISO);
  99     pinmap_pinout(sclk, PinMap_SPI_SCLK);
 100     if (ssel != NC) {
 101         pinmap_pinout(ssel, PinMap_SPI_SSEL);
 102     }
 103 }
 104
 105 void spi_free(spi_t *obj) {
 106     // [TODO]
 107 }
 108
 109 void spi_format(spi_t *obj, int bits, int mode, int slave) {
 110     MBED_ASSERT((bits == 8) || (bits == 16));
 111     MBED_ASSERT((mode >= 0) && (mode <= 3));
 112
 113     uint8_t polarity = (mode & 0x2) ? 1 : 0;
 114     uint8_t phase = (mode & 0x1) ? 1 : 0;
 115     uint8_t c1_data = ((!slave) << 4) | (polarity << 3) | (phase << 2);
 116
 117     // clear MSTR, CPOL and CPHA bits
 118     obj->spi->C1 &= ~(0x7 << 2);
 119
 120     // write new value
 121     obj->spi->C1 |= c1_data;
 122     if (bits == 8) {
 123         obj->spi->C2 &= ~SPI_C2_SPIMODE_MASK;
 124     } else {
 125         obj->spi->C2 |= SPI_C2_SPIMODE_MASK;
 126     }
 127 }
 128
 129 void spi_frequency(spi_t *obj, int hz) {
 130     uint32_t error = 0;
 131     uint32_t p_error = 0xffffffff;
 132     uint32_t ref = 0;
 133     uint8_t  spr = 0;
 134     uint8_t  ref_spr = 0;
 135     uint8_t  ref_prescaler = 0;
 136
 137     // bus clk
 138     uint32_t PCLK = SystemCoreClock / (((SIM->CLKDIV1 & SIM_CLKDIV1_OUTDIV4_MASK) >> SIM_CLKDIV1_OUTDIV4_SHIFT) + 1);
 139     uint8_t prescaler = 1;
 140     uint8_t divisor = 2;
 141
 142     for (prescaler = 1; prescaler <= 8; prescaler++) {
 143         divisor = 2;
 144         for (spr = 0; spr <= 8; spr++, divisor *= 2) {
 145             ref = PCLK / (prescaler*divisor);
 146             if (ref > (uint32_t)hz)
 147                 continue;
 148             error = hz - ref;
 149             if (error < p_error) {
 150                 ref_spr = spr;
 151                 ref_prescaler = prescaler - 1;
 152                 p_error = error;
 153             }
 154         }
 155     }
 156
 157     // set SPPR and SPR
 158     obj->spi->BR = ((ref_prescaler & 0x7) << 4) | (ref_spr & 0xf);
 159 }
 160
 161 static inline int spi_writeable(spi_t * obj) {
 162     return (obj->spi->S & SPI_S_SPTEF_MASK) ? 1 : 0;
 163 }
 164
 165 static inline int spi_readable(spi_t * obj) {
 166     return (obj->spi->S & SPI_S_SPRF_MASK) ? 1 : 0;
 167 }
 168
 169 int spi_master_write(spi_t *obj, int value) {
 170     int ret;
 171     if (obj->spi->C2 & SPI_C2_SPIMODE_MASK) {
 172         // 16bit
 173         while(!spi_writeable(obj));
 174         obj->spi->DL = (value & 0xff);
 175         obj->spi->DH = ((value >> 8) & 0xff);
 176
 177         // wait rx buffer full
 178         while (!spi_readable(obj));
 179         ret = obj->spi->DH;
 180         ret = (ret << 8) | obj->spi->DL;
 181     } else {
 182         //8bit
 183         while(!spi_writeable(obj));
 184         obj->spi->DL = (value & 0xff);
 185
 186         // wait rx buffer full
 187         while (!spi_readable(obj));
 188         ret = (obj->spi->DL & 0xff);
 189     }
 190
 191     return ret;
 192 }
 193
 194 int spi_slave_receive(spi_t *obj) {
 195     return spi_readable(obj);
 196 }
 197
 198 int spi_slave_read(spi_t *obj) {
 199     int ret;
 200     if (obj->spi->C2 & SPI_C2_SPIMODE_MASK) {
 201         ret = obj->spi->DH;
 202         ret = ((ret << 8) | obj->spi->DL);
 203     } else {
 204         ret = obj->spi->DL;
 205     }
 206     return ret;
 207 }
 208
 209 void spi_slave_write(spi_t *obj, int value) {
 210     while (!spi_writeable(obj));
 211     if (obj->spi->C2 & SPI_C2_SPIMODE_MASK) {
 212         obj->spi->DL = (value & 0xff);
 213         obj->spi->DH = ((value >> 8) & 0xff);
 214     } else {
 215         obj->spi->DL = value;
 216     }
 217
 218 }