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mbed library sources

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targets/hal/TARGET_STM/TARGET_STM32F4XX/spi_api.c@20:4263a77256ae, 2013-09-10 (annotated)

Committer:
bogdanm
Date:
Tue Sep 10 15:14:19 2013 +0300
Revision:
20:4263a77256ae
Child:
227:7bd0639b8911
Sync with git revision 171dda705c947bf910926a0b73d6a4797802554d

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bogdanm 20:4263a77256ae 1 /* mbed Microcontroller Library
bogdanm 20:4263a77256ae 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 20:4263a77256ae 3 *
bogdanm 20:4263a77256ae 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 20:4263a77256ae 5 * you may not use this file except in compliance with the License.
bogdanm 20:4263a77256ae 6 * You may obtain a copy of the License at
bogdanm 20:4263a77256ae 7 *
bogdanm 20:4263a77256ae 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 20:4263a77256ae 9 *
bogdanm 20:4263a77256ae 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 20:4263a77256ae 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 20:4263a77256ae 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 20:4263a77256ae 13 * See the License for the specific language governing permissions and
bogdanm 20:4263a77256ae 14 * limitations under the License.
bogdanm 20:4263a77256ae 15 */
bogdanm 20:4263a77256ae 16 #include "spi_api.h"
bogdanm 20:4263a77256ae 17
bogdanm 20:4263a77256ae 18 #if DEVICE_SPI
bogdanm 20:4263a77256ae 19 #include <math.h>
bogdanm 20:4263a77256ae 20
bogdanm 20:4263a77256ae 21 #include "cmsis.h"
bogdanm 20:4263a77256ae 22 #include "pinmap.h"
bogdanm 20:4263a77256ae 23 #include "error.h"
bogdanm 20:4263a77256ae 24
bogdanm 20:4263a77256ae 25 static const PinMap PinMap_SPI_SCLK[] = {
bogdanm 20:4263a77256ae 26 {PA_5, SPI_1, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 27 {PB_3, SPI_1, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 28 {PB_3, SPI_3, STM_PIN_DATA(2, 6)},
bogdanm 20:4263a77256ae 29 {PB_10, SPI_2, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 30 {PB_13, SPI_2, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 31 {PC_10, SPI_3, STM_PIN_DATA(2, 6)},
bogdanm 20:4263a77256ae 32 {NC, NC, 0}
bogdanm 20:4263a77256ae 33 };
bogdanm 20:4263a77256ae 34
bogdanm 20:4263a77256ae 35 static const PinMap PinMap_SPI_MOSI[] = {
bogdanm 20:4263a77256ae 36 {PA_7, SPI_1, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 37 {PB_5, SPI_1, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 38 {PB_5, SPI_3, STM_PIN_DATA(2, 6)},
bogdanm 20:4263a77256ae 39 {PB_15, SPI_2, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 40 {PC_3, SPI_2, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 41 {PC_12, SPI_3, STM_PIN_DATA(2, 6)},
bogdanm 20:4263a77256ae 42 {NC, NC, 0}
bogdanm 20:4263a77256ae 43 };
bogdanm 20:4263a77256ae 44
bogdanm 20:4263a77256ae 45 static const PinMap PinMap_SPI_MISO[] = {
bogdanm 20:4263a77256ae 46 {PA_6, SPI_1, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 47 {PB_4, SPI_1, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 48 {PB_4, SPI_3, STM_PIN_DATA(2, 6)},
bogdanm 20:4263a77256ae 49 {PB_14, SPI_2, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 50 {PC_2, SPI_2, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 51 {PC_11, SPI_3, STM_PIN_DATA(2, 6)},
bogdanm 20:4263a77256ae 52 {NC, NC, 0}
bogdanm 20:4263a77256ae 53 };
bogdanm 20:4263a77256ae 54
bogdanm 20:4263a77256ae 55 static const PinMap PinMap_SPI_SSEL[] = {
bogdanm 20:4263a77256ae 56 {PA_4, SPI_1, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 57 {PA_4, SPI_3, STM_PIN_DATA(2, 6)},
bogdanm 20:4263a77256ae 58 {PA_15, SPI_1, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 59 {PA_15, SPI_3, STM_PIN_DATA(2, 6)},
bogdanm 20:4263a77256ae 60 {PB_9, SPI_2, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 61 {PB_12, SPI_2, STM_PIN_DATA(2, 5)},
bogdanm 20:4263a77256ae 62 {NC, NC, 0}
bogdanm 20:4263a77256ae 63 };
bogdanm 20:4263a77256ae 64
bogdanm 20:4263a77256ae 65
bogdanm 20:4263a77256ae 66 static inline int ssp_disable(spi_t *obj);
bogdanm 20:4263a77256ae 67 static inline int ssp_enable(spi_t *obj);
bogdanm 20:4263a77256ae 68
bogdanm 20:4263a77256ae 69 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
bogdanm 20:4263a77256ae 70 // determine the SPI to use
bogdanm 20:4263a77256ae 71 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
bogdanm 20:4263a77256ae 72 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
bogdanm 20:4263a77256ae 73 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
bogdanm 20:4263a77256ae 74 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
bogdanm 20:4263a77256ae 75 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
bogdanm 20:4263a77256ae 76 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
bogdanm 20:4263a77256ae 77 obj->spi = (SPI_TypeDef*)pinmap_merge(spi_data, spi_cntl);
bogdanm 20:4263a77256ae 78 if ((int)obj->spi == NC) {
bogdanm 20:4263a77256ae 79 error("SPI pinout mapping failed");
bogdanm 20:4263a77256ae 80 }
bogdanm 20:4263a77256ae 81
bogdanm 20:4263a77256ae 82 // enable power and clocking
bogdanm 20:4263a77256ae 83 switch ((int)obj->spi) {
bogdanm 20:4263a77256ae 84 case SPI_1:
bogdanm 20:4263a77256ae 85 RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN | RCC_AHB1ENR_GPIOBEN;
bogdanm 20:4263a77256ae 86 RCC->APB2ENR |= RCC_APB2ENR_SPI1EN;
bogdanm 20:4263a77256ae 87 break;
bogdanm 20:4263a77256ae 88 case SPI_2:
bogdanm 20:4263a77256ae 89 RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN | RCC_AHB1ENR_GPIOCEN;
bogdanm 20:4263a77256ae 90 RCC->APB1ENR |= RCC_APB1ENR_SPI2EN;
bogdanm 20:4263a77256ae 91 break;
bogdanm 20:4263a77256ae 92 case SPI_3:
bogdanm 20:4263a77256ae 93 RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN | RCC_AHB1ENR_GPIOCEN;
bogdanm 20:4263a77256ae 94 RCC->APB1ENR |= RCC_APB1ENR_SPI3EN;
bogdanm 20:4263a77256ae 95 break;
bogdanm 20:4263a77256ae 96 }
bogdanm 20:4263a77256ae 97
bogdanm 20:4263a77256ae 98
bogdanm 20:4263a77256ae 99 // set default format and frequency
bogdanm 20:4263a77256ae 100 if (ssel == NC) {
bogdanm 20:4263a77256ae 101 spi_format(obj, 8, 0, 0); // 8 bits, mode 0, master
bogdanm 20:4263a77256ae 102 } else {
bogdanm 20:4263a77256ae 103 spi_format(obj, 8, 0, 1); // 8 bits, mode 0, slave
bogdanm 20:4263a77256ae 104 }
bogdanm 20:4263a77256ae 105 spi_frequency(obj, 1000000);
bogdanm 20:4263a77256ae 106
bogdanm 20:4263a77256ae 107 // enable the ssp channel
bogdanm 20:4263a77256ae 108 ssp_enable(obj);
bogdanm 20:4263a77256ae 109
bogdanm 20:4263a77256ae 110 // pin out the spi pins
bogdanm 20:4263a77256ae 111 pinmap_pinout(mosi, PinMap_SPI_MOSI);
bogdanm 20:4263a77256ae 112 pinmap_pinout(miso, PinMap_SPI_MISO);
bogdanm 20:4263a77256ae 113 pinmap_pinout(sclk, PinMap_SPI_SCLK);
bogdanm 20:4263a77256ae 114 if (ssel != NC) {
bogdanm 20:4263a77256ae 115 pinmap_pinout(ssel, PinMap_SPI_SSEL);
bogdanm 20:4263a77256ae 116 }
bogdanm 20:4263a77256ae 117 else {
bogdanm 20:4263a77256ae 118 // Use software slave management
bogdanm 20:4263a77256ae 119 obj->spi->CR1 |= SPI_CR1_SSM | SPI_CR1_SSI;
bogdanm 20:4263a77256ae 120 }
bogdanm 20:4263a77256ae 121 }
bogdanm 20:4263a77256ae 122
bogdanm 20:4263a77256ae 123 void spi_free(spi_t *obj) {}
bogdanm 20:4263a77256ae 124
bogdanm 20:4263a77256ae 125 void spi_format(spi_t *obj, int bits, int mode, int slave) {
bogdanm 20:4263a77256ae 126 ssp_disable(obj);
bogdanm 20:4263a77256ae 127
bogdanm 20:4263a77256ae 128 if (!(bits == 8 || bits == 16) || !(mode >= 0 && mode <= 3)) {
bogdanm 20:4263a77256ae 129 error("SPI format error");
bogdanm 20:4263a77256ae 130 }
bogdanm 20:4263a77256ae 131
bogdanm 20:4263a77256ae 132
bogdanm 20:4263a77256ae 133 int polarity = (mode & 0x2) ? 1 : 0;
bogdanm 20:4263a77256ae 134 int phase = (mode & 0x1) ? 1 : 0;
bogdanm 20:4263a77256ae 135
bogdanm 20:4263a77256ae 136 obj->spi->CR1 &= ~0x807;
bogdanm 20:4263a77256ae 137 obj->spi->CR1 |= ((phase) ? 1 : 0) << 0 |
bogdanm 20:4263a77256ae 138 ((polarity) ? 1 : 0) << 1 |
bogdanm 20:4263a77256ae 139 ((slave) ? 0: 1) << 2 |
bogdanm 20:4263a77256ae 140 ((bits == 16) ? 1 : 0) << 11;
bogdanm 20:4263a77256ae 141
bogdanm 20:4263a77256ae 142 if (obj->spi->SR & SPI_SR_MODF) {
bogdanm 20:4263a77256ae 143 obj->spi->CR1 = obj->spi->CR1;
bogdanm 20:4263a77256ae 144 }
bogdanm 20:4263a77256ae 145
bogdanm 20:4263a77256ae 146 ssp_enable(obj);
bogdanm 20:4263a77256ae 147 }
bogdanm 20:4263a77256ae 148
bogdanm 20:4263a77256ae 149 void spi_frequency(spi_t *obj, int hz) {
bogdanm 20:4263a77256ae 150 ssp_disable(obj);
bogdanm 20:4263a77256ae 151
bogdanm 20:4263a77256ae 152 // SPI1 runs from PCLK2, which runs at SystemCoreClock / 2. SPI2 and SPI3
bogdanm 20:4263a77256ae 153 // run from PCLK1, which runs at SystemCoreClock / 4.
bogdanm 20:4263a77256ae 154 uint32_t PCLK = SystemCoreClock;
bogdanm 20:4263a77256ae 155 switch ((int)obj->spi) {
bogdanm 20:4263a77256ae 156 case SPI_1: PCLK = PCLK >> 1; break;
bogdanm 20:4263a77256ae 157 case SPI_2: PCLK = PCLK >> 2; break;
bogdanm 20:4263a77256ae 158 case SPI_3: PCLK = PCLK >> 2; break;
bogdanm 20:4263a77256ae 159 }
bogdanm 20:4263a77256ae 160
bogdanm 20:4263a77256ae 161 // Choose the baud rate divisor (between 2 and 256)
bogdanm 20:4263a77256ae 162 uint32_t divisor = PCLK / hz;
bogdanm 20:4263a77256ae 163
bogdanm 20:4263a77256ae 164 // Find the nearest power-of-2
bogdanm 20:4263a77256ae 165 divisor = divisor > 0 ? divisor-1 : 0;
bogdanm 20:4263a77256ae 166 divisor |= divisor >> 1;
bogdanm 20:4263a77256ae 167 divisor |= divisor >> 2;
bogdanm 20:4263a77256ae 168 divisor |= divisor >> 4;
bogdanm 20:4263a77256ae 169 divisor |= divisor >> 8;
bogdanm 20:4263a77256ae 170 divisor |= divisor >> 16;
bogdanm 20:4263a77256ae 171 divisor++;
bogdanm 20:4263a77256ae 172
bogdanm 20:4263a77256ae 173 uint32_t baud_rate = __builtin_ffs(divisor) - 1;
bogdanm 20:4263a77256ae 174 baud_rate = baud_rate > 0x7 ? 0x7 : baud_rate;
bogdanm 20:4263a77256ae 175
bogdanm 20:4263a77256ae 176 obj->spi->CR1 &= ~(0x7 << 3);
bogdanm 20:4263a77256ae 177 obj->spi->CR1 |= baud_rate << 3;
bogdanm 20:4263a77256ae 178
bogdanm 20:4263a77256ae 179 ssp_enable(obj);
bogdanm 20:4263a77256ae 180 }
bogdanm 20:4263a77256ae 181
bogdanm 20:4263a77256ae 182 static inline int ssp_disable(spi_t *obj) {
bogdanm 20:4263a77256ae 183 // TODO: Follow the instructions in 25.3.8 for safely disabling the SPI
bogdanm 20:4263a77256ae 184 return obj->spi->CR1 &= ~SPI_CR1_SPE;
bogdanm 20:4263a77256ae 185 }
bogdanm 20:4263a77256ae 186
bogdanm 20:4263a77256ae 187 static inline int ssp_enable(spi_t *obj) {
bogdanm 20:4263a77256ae 188 return obj->spi->CR1 |= SPI_CR1_SPE;
bogdanm 20:4263a77256ae 189 }
bogdanm 20:4263a77256ae 190
bogdanm 20:4263a77256ae 191 static inline int ssp_readable(spi_t *obj) {
bogdanm 20:4263a77256ae 192 return obj->spi->SR & SPI_SR_RXNE;
bogdanm 20:4263a77256ae 193 }
bogdanm 20:4263a77256ae 194
bogdanm 20:4263a77256ae 195 static inline int ssp_writeable(spi_t *obj) {
bogdanm 20:4263a77256ae 196 return obj->spi->SR & SPI_SR_TXE;
bogdanm 20:4263a77256ae 197 }
bogdanm 20:4263a77256ae 198
bogdanm 20:4263a77256ae 199 static inline void ssp_write(spi_t *obj, int value) {
bogdanm 20:4263a77256ae 200 while (!ssp_writeable(obj));
bogdanm 20:4263a77256ae 201 obj->spi->DR = value;
bogdanm 20:4263a77256ae 202 }
bogdanm 20:4263a77256ae 203
bogdanm 20:4263a77256ae 204 static inline int ssp_read(spi_t *obj) {
bogdanm 20:4263a77256ae 205 while (!ssp_readable(obj));
bogdanm 20:4263a77256ae 206 return obj->spi->DR;
bogdanm 20:4263a77256ae 207 }
bogdanm 20:4263a77256ae 208
bogdanm 20:4263a77256ae 209 static inline int ssp_busy(spi_t *obj) {
bogdanm 20:4263a77256ae 210 return (obj->spi->SR & SPI_SR_BSY) ? (1) : (0);
bogdanm 20:4263a77256ae 211 }
bogdanm 20:4263a77256ae 212
bogdanm 20:4263a77256ae 213 int spi_master_write(spi_t *obj, int value) {
bogdanm 20:4263a77256ae 214 ssp_write(obj, value);
bogdanm 20:4263a77256ae 215 return ssp_read(obj);
bogdanm 20:4263a77256ae 216 }
bogdanm 20:4263a77256ae 217
bogdanm 20:4263a77256ae 218 int spi_slave_receive(spi_t *obj) {
bogdanm 20:4263a77256ae 219 return (ssp_readable(obj) && !ssp_busy(obj)) ? (1) : (0);
bogdanm 20:4263a77256ae 220 };
bogdanm 20:4263a77256ae 221
bogdanm 20:4263a77256ae 222 int spi_slave_read(spi_t *obj) {
bogdanm 20:4263a77256ae 223 return obj->spi->DR;
bogdanm 20:4263a77256ae 224 }
bogdanm 20:4263a77256ae 225
bogdanm 20:4263a77256ae 226 void spi_slave_write(spi_t *obj, int value) {
bogdanm 20:4263a77256ae 227 while (ssp_writeable(obj) == 0) ;
bogdanm 20:4263a77256ae 228 obj->spi->DR = value;
bogdanm 20:4263a77256ae 229 }
bogdanm 20:4263a77256ae 230
bogdanm 20:4263a77256ae 231 int spi_busy(spi_t *obj) {
bogdanm 20:4263a77256ae 232 return ssp_busy(obj);
bogdanm 20:4263a77256ae 233 }
bogdanm 20:4263a77256ae 234
bogdanm 20:4263a77256ae 235 #endif