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Dependents:   SPI_slave_frdm

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targets/hal/TARGET_Freescale/TARGET_KL46Z/spi_api.c@31:42176bc3c368, 2013-09-25 (annotated)

Committer:
mbed_official
Date:
Wed Sep 25 11:30:05 2013 +0100
Revision:
31:42176bc3c368
Child:
33:e214068ab66c
Synchronized with git revision f580c008b139a952d38ac5c7c53bbae375739c67

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 31:42176bc3c368 1 /* mbed Microcontroller Library
mbed_official 31:42176bc3c368 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 31:42176bc3c368 3 *
mbed_official 31:42176bc3c368 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 31:42176bc3c368 5 * you may not use this file except in compliance with the License.
mbed_official 31:42176bc3c368 6 * You may obtain a copy of the License at
mbed_official 31:42176bc3c368 7 *
mbed_official 31:42176bc3c368 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 31:42176bc3c368 9 *
mbed_official 31:42176bc3c368 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 31:42176bc3c368 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 31:42176bc3c368 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 31:42176bc3c368 13 * See the License for the specific language governing permissions and
mbed_official 31:42176bc3c368 14 * limitations under the License.
mbed_official 31:42176bc3c368 15 */
mbed_official 31:42176bc3c368 16 #include "spi_api.h"
mbed_official 31:42176bc3c368 17
mbed_official 31:42176bc3c368 18 #include <math.h>
mbed_official 31:42176bc3c368 19
mbed_official 31:42176bc3c368 20 #include "cmsis.h"
mbed_official 31:42176bc3c368 21 #include "pinmap.h"
mbed_official 31:42176bc3c368 22 #include "error.h"
mbed_official 31:42176bc3c368 23
mbed_official 31:42176bc3c368 24 static const PinMap PinMap_SPI_SCLK[] = {
mbed_official 31:42176bc3c368 25 {PTA15, SPI_0, 2},
mbed_official 31:42176bc3c368 26 {PTB11, SPI_1, 2},
mbed_official 31:42176bc3c368 27 {PTC5, SPI_0, 2},
mbed_official 31:42176bc3c368 28 {PTD1, SPI_0, 2},
mbed_official 31:42176bc3c368 29 {PTD5, SPI_1, 2},
mbed_official 31:42176bc3c368 30 {PTE2, SPI_1, 2},
mbed_official 31:42176bc3c368 31 {NC , NC , 0}
mbed_official 31:42176bc3c368 32 };
mbed_official 31:42176bc3c368 33
mbed_official 31:42176bc3c368 34 static const PinMap PinMap_SPI_MOSI[] = {
mbed_official 31:42176bc3c368 35 {PTA16, SPI_0, 2},
mbed_official 31:42176bc3c368 36 {PTA17, SPI_0, 5},
mbed_official 31:42176bc3c368 37 {PTB16, SPI_1, 2},
mbed_official 31:42176bc3c368 38 {PTB17, SPI_1, 5},
mbed_official 31:42176bc3c368 39 {PTC6, SPI_0, 2},
mbed_official 31:42176bc3c368 40 {PTC7, SPI_0, 5},
mbed_official 31:42176bc3c368 41 {PTD2, SPI_0, 2},
mbed_official 31:42176bc3c368 42 {PTD3, SPI_0, 5},
mbed_official 31:42176bc3c368 43 {PTD6, SPI_1, 2},
mbed_official 31:42176bc3c368 44 {PTD7, SPI_1, 5},
mbed_official 31:42176bc3c368 45 {PTE1, SPI_1, 2},
mbed_official 31:42176bc3c368 46 {PTE3, SPI_1, 5},
mbed_official 31:42176bc3c368 47 {NC , NC , 0}
mbed_official 31:42176bc3c368 48 };
mbed_official 31:42176bc3c368 49
mbed_official 31:42176bc3c368 50 static const PinMap PinMap_SPI_MISO[] = {
mbed_official 31:42176bc3c368 51 {PTA16, SPI_0, 5},
mbed_official 31:42176bc3c368 52 {PTA17, SPI_0, 2},
mbed_official 31:42176bc3c368 53 {PTB16, SPI_1, 5},
mbed_official 31:42176bc3c368 54 {PTB17, SPI_1, 2},
mbed_official 31:42176bc3c368 55 {PTC6, SPI_0, 5},
mbed_official 31:42176bc3c368 56 {PTC7, SPI_0, 2},
mbed_official 31:42176bc3c368 57 {PTD2, SPI_0, 5},
mbed_official 31:42176bc3c368 58 {PTD3, SPI_0, 2},
mbed_official 31:42176bc3c368 59 {PTD6, SPI_1, 5},
mbed_official 31:42176bc3c368 60 {PTD7, SPI_1, 2},
mbed_official 31:42176bc3c368 61 {PTE1, SPI_1, 5},
mbed_official 31:42176bc3c368 62 {PTE3, SPI_1, 2},
mbed_official 31:42176bc3c368 63 {NC , NC , 0}
mbed_official 31:42176bc3c368 64 };
mbed_official 31:42176bc3c368 65
mbed_official 31:42176bc3c368 66 static const PinMap PinMap_SPI_SSEL[] = {
mbed_official 31:42176bc3c368 67 {PTA14, SPI_0, 2},
mbed_official 31:42176bc3c368 68 {PTB10, SPI_1, 2},
mbed_official 31:42176bc3c368 69 {PTC4, SPI_0, 2},
mbed_official 31:42176bc3c368 70 {PTD0, SPI_0, 2},
mbed_official 31:42176bc3c368 71 {PTD4, SPI_1, 2},
mbed_official 31:42176bc3c368 72 {PTE4, SPI_1, 2},
mbed_official 31:42176bc3c368 73 {NC , NC , 0}
mbed_official 31:42176bc3c368 74 };
mbed_official 31:42176bc3c368 75
mbed_official 31:42176bc3c368 76 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
mbed_official 31:42176bc3c368 77 // determine the SPI to use
mbed_official 31:42176bc3c368 78 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
mbed_official 31:42176bc3c368 79 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
mbed_official 31:42176bc3c368 80 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
mbed_official 31:42176bc3c368 81 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
mbed_official 31:42176bc3c368 82 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
mbed_official 31:42176bc3c368 83 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
mbed_official 31:42176bc3c368 84
mbed_official 31:42176bc3c368 85 obj->spi = (SPI_Type*)pinmap_merge(spi_data, spi_cntl);
mbed_official 31:42176bc3c368 86 if ((int)obj->spi == NC) {
mbed_official 31:42176bc3c368 87 error("SPI pinout mapping failed");
mbed_official 31:42176bc3c368 88 }
mbed_official 31:42176bc3c368 89
mbed_official 31:42176bc3c368 90 // enable power and clocking
mbed_official 31:42176bc3c368 91 switch ((int)obj->spi) {
mbed_official 31:42176bc3c368 92 case SPI_0: SIM->SCGC5 |= 1 << 11; SIM->SCGC4 |= 1 << 22; break;
mbed_official 31:42176bc3c368 93 case SPI_1: SIM->SCGC5 |= 1 << 13; SIM->SCGC4 |= 1 << 23; break;
mbed_official 31:42176bc3c368 94 }
mbed_official 31:42176bc3c368 95
mbed_official 31:42176bc3c368 96 // set default format and frequency
mbed_official 31:42176bc3c368 97 if (ssel == NC) {
mbed_official 31:42176bc3c368 98 spi_format(obj, 8, 0, 0); // 8 bits, mode 0, master
mbed_official 31:42176bc3c368 99 } else {
mbed_official 31:42176bc3c368 100 spi_format(obj, 8, 0, 1); // 8 bits, mode 0, slave
mbed_official 31:42176bc3c368 101 }
mbed_official 31:42176bc3c368 102 spi_frequency(obj, 1000000);
mbed_official 31:42176bc3c368 103
mbed_official 31:42176bc3c368 104 // enable SPI
mbed_official 31:42176bc3c368 105 obj->spi->C1 |= SPI_C1_SPE_MASK;
mbed_official 31:42176bc3c368 106
mbed_official 31:42176bc3c368 107 // pin out the spi pins
mbed_official 31:42176bc3c368 108 pinmap_pinout(mosi, PinMap_SPI_MOSI);
mbed_official 31:42176bc3c368 109 pinmap_pinout(miso, PinMap_SPI_MISO);
mbed_official 31:42176bc3c368 110 pinmap_pinout(sclk, PinMap_SPI_SCLK);
mbed_official 31:42176bc3c368 111 if (ssel != NC) {
mbed_official 31:42176bc3c368 112 pinmap_pinout(ssel, PinMap_SPI_SSEL);
mbed_official 31:42176bc3c368 113 }
mbed_official 31:42176bc3c368 114 }
mbed_official 31:42176bc3c368 115
mbed_official 31:42176bc3c368 116 void spi_free(spi_t *obj) {
mbed_official 31:42176bc3c368 117 // [TODO]
mbed_official 31:42176bc3c368 118 }
mbed_official 31:42176bc3c368 119 void spi_format(spi_t *obj, int bits, int mode, int slave) {
mbed_official 31:42176bc3c368 120 if (bits != 8) {
mbed_official 31:42176bc3c368 121 error("Only 8bits SPI supported");
mbed_official 31:42176bc3c368 122 }
mbed_official 31:42176bc3c368 123
mbed_official 31:42176bc3c368 124 if ((mode < 0) || (mode > 3)) {
mbed_official 31:42176bc3c368 125 error("SPI mode unsupported");
mbed_official 31:42176bc3c368 126 }
mbed_official 31:42176bc3c368 127
mbed_official 31:42176bc3c368 128 uint8_t polarity = (mode & 0x2) ? 1 : 0;
mbed_official 31:42176bc3c368 129 uint8_t phase = (mode & 0x1) ? 1 : 0;
mbed_official 31:42176bc3c368 130 uint8_t c1_data = ((!slave) << 4) | (polarity << 3) | (phase << 2);
mbed_official 31:42176bc3c368 131
mbed_official 31:42176bc3c368 132 // clear MSTR, CPOL and CPHA bits
mbed_official 31:42176bc3c368 133 obj->spi->C1 &= ~(0x7 << 2);
mbed_official 31:42176bc3c368 134
mbed_official 31:42176bc3c368 135 // write new value
mbed_official 31:42176bc3c368 136 obj->spi->C1 |= c1_data;
mbed_official 31:42176bc3c368 137 }
mbed_official 31:42176bc3c368 138
mbed_official 31:42176bc3c368 139 void spi_frequency(spi_t *obj, int hz) {
mbed_official 31:42176bc3c368 140 uint32_t error = 0;
mbed_official 31:42176bc3c368 141 uint32_t p_error = 0xffffffff;
mbed_official 31:42176bc3c368 142 uint32_t ref = 0;
mbed_official 31:42176bc3c368 143 uint8_t spr = 0;
mbed_official 31:42176bc3c368 144 uint8_t ref_spr = 0;
mbed_official 31:42176bc3c368 145 uint8_t ref_prescaler = 0;
mbed_official 31:42176bc3c368 146
mbed_official 31:42176bc3c368 147 // bus clk
mbed_official 31:42176bc3c368 148 uint32_t PCLK = 48000000u;
mbed_official 31:42176bc3c368 149 uint8_t prescaler = 1;
mbed_official 31:42176bc3c368 150 uint8_t divisor = 2;
mbed_official 31:42176bc3c368 151
mbed_official 31:42176bc3c368 152 for (prescaler = 1; prescaler <= 8; prescaler++) {
mbed_official 31:42176bc3c368 153 divisor = 2;
mbed_official 31:42176bc3c368 154 for (spr = 0; spr <= 8; spr++, divisor *= 2) {
mbed_official 31:42176bc3c368 155 ref = PCLK / (prescaler*divisor);
mbed_official 31:42176bc3c368 156 if (ref > (uint32_t)hz)
mbed_official 31:42176bc3c368 157 continue;
mbed_official 31:42176bc3c368 158 error = hz - ref;
mbed_official 31:42176bc3c368 159 if (error < p_error) {
mbed_official 31:42176bc3c368 160 ref_spr = spr;
mbed_official 31:42176bc3c368 161 ref_prescaler = prescaler - 1;
mbed_official 31:42176bc3c368 162 p_error = error;
mbed_official 31:42176bc3c368 163 }
mbed_official 31:42176bc3c368 164 }
mbed_official 31:42176bc3c368 165 }
mbed_official 31:42176bc3c368 166
mbed_official 31:42176bc3c368 167 // set SPPR and SPR
mbed_official 31:42176bc3c368 168 obj->spi->BR = ((ref_prescaler & 0x7) << 4) | (ref_spr & 0xf);
mbed_official 31:42176bc3c368 169 }
mbed_official 31:42176bc3c368 170
mbed_official 31:42176bc3c368 171 static inline int spi_writeable(spi_t * obj) {
mbed_official 31:42176bc3c368 172 return (obj->spi->S & SPI_S_SPTEF_MASK) ? 1 : 0;
mbed_official 31:42176bc3c368 173 }
mbed_official 31:42176bc3c368 174
mbed_official 31:42176bc3c368 175 static inline int spi_readable(spi_t * obj) {
mbed_official 31:42176bc3c368 176 return (obj->spi->S & SPI_S_SPRF_MASK) ? 1 : 0;
mbed_official 31:42176bc3c368 177 }
mbed_official 31:42176bc3c368 178
mbed_official 31:42176bc3c368 179 int spi_master_write(spi_t *obj, int value) {
mbed_official 31:42176bc3c368 180 // wait tx buffer empty
mbed_official 31:42176bc3c368 181 while(!spi_writeable(obj));
mbed_official 31:42176bc3c368 182 obj->spi->D = (value & 0xff);
mbed_official 31:42176bc3c368 183
mbed_official 31:42176bc3c368 184 // wait rx buffer full
mbed_official 31:42176bc3c368 185 while (!spi_readable(obj));
mbed_official 31:42176bc3c368 186 return obj->spi->D & 0xff;
mbed_official 31:42176bc3c368 187 }
mbed_official 31:42176bc3c368 188
mbed_official 31:42176bc3c368 189 int spi_slave_receive(spi_t *obj) {
mbed_official 31:42176bc3c368 190 return spi_readable(obj);
mbed_official 31:42176bc3c368 191 }
mbed_official 31:42176bc3c368 192
mbed_official 31:42176bc3c368 193 int spi_slave_read(spi_t *obj) {
mbed_official 31:42176bc3c368 194 return obj->spi->D;
mbed_official 31:42176bc3c368 195 }
mbed_official 31:42176bc3c368 196
mbed_official 31:42176bc3c368 197 void spi_slave_write(spi_t *obj, int value) {
mbed_official 31:42176bc3c368 198 while (!spi_writeable(obj));
mbed_official 31:42176bc3c368 199 obj->spi->D = value;
mbed_official 31:42176bc3c368 200 }