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targets/hal/TARGET_NXP/TARGET_LPC23XX/spi_api.c@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
Child:
144:ef7eb2e8f9f7
Initial commit on mbed-dev



Replaces mbed-src (now inactive)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 0:9b334a45a8ff 1 /* mbed Microcontroller Library
bogdanm 0:9b334a45a8ff 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 0:9b334a45a8ff 3 *
bogdanm 0:9b334a45a8ff 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 0:9b334a45a8ff 5 * you may not use this file except in compliance with the License.
bogdanm 0:9b334a45a8ff 6 * You may obtain a copy of the License at
bogdanm 0:9b334a45a8ff 7 *
bogdanm 0:9b334a45a8ff 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 0:9b334a45a8ff 9 *
bogdanm 0:9b334a45a8ff 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 0:9b334a45a8ff 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 0:9b334a45a8ff 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 0:9b334a45a8ff 13 * See the License for the specific language governing permissions and
bogdanm 0:9b334a45a8ff 14 * limitations under the License.
bogdanm 0:9b334a45a8ff 15 */
bogdanm 0:9b334a45a8ff 16 #include "mbed_assert.h"
bogdanm 0:9b334a45a8ff 17 #include <math.h>
bogdanm 0:9b334a45a8ff 18
bogdanm 0:9b334a45a8ff 19 #include "spi_api.h"
bogdanm 0:9b334a45a8ff 20 #include "cmsis.h"
bogdanm 0:9b334a45a8ff 21 #include "pinmap.h"
bogdanm 0:9b334a45a8ff 22 #include "mbed_error.h"
bogdanm 0:9b334a45a8ff 23
bogdanm 0:9b334a45a8ff 24 static const PinMap PinMap_SPI_SCLK[] = {
bogdanm 0:9b334a45a8ff 25 {P0_7 , SPI_1, 2},
bogdanm 0:9b334a45a8ff 26 {P0_15, SPI_0, 2},
bogdanm 0:9b334a45a8ff 27 {P1_20, SPI_0, 3},
bogdanm 0:9b334a45a8ff 28 {P1_31, SPI_1, 2},
bogdanm 0:9b334a45a8ff 29 {NC , NC , 0}
bogdanm 0:9b334a45a8ff 30 };
bogdanm 0:9b334a45a8ff 31
bogdanm 0:9b334a45a8ff 32 static const PinMap PinMap_SPI_MOSI[] = {
bogdanm 0:9b334a45a8ff 33 {P0_9 , SPI_1, 2},
bogdanm 0:9b334a45a8ff 34 {P0_13, SPI_1, 2},
bogdanm 0:9b334a45a8ff 35 {P0_18, SPI_0, 2},
bogdanm 0:9b334a45a8ff 36 {P1_24, SPI_0, 3},
bogdanm 0:9b334a45a8ff 37 {NC , NC , 0}
bogdanm 0:9b334a45a8ff 38 };
bogdanm 0:9b334a45a8ff 39
bogdanm 0:9b334a45a8ff 40 static const PinMap PinMap_SPI_MISO[] = {
bogdanm 0:9b334a45a8ff 41 {P0_8 , SPI_1, 2},
bogdanm 0:9b334a45a8ff 42 {P0_12, SPI_1, 2},
bogdanm 0:9b334a45a8ff 43 {P0_17, SPI_0, 2},
bogdanm 0:9b334a45a8ff 44 {P1_23, SPI_0, 3},
bogdanm 0:9b334a45a8ff 45 {NC , NC , 0}
bogdanm 0:9b334a45a8ff 46 };
bogdanm 0:9b334a45a8ff 47
bogdanm 0:9b334a45a8ff 48 static const PinMap PinMap_SPI_SSEL[] = {
bogdanm 0:9b334a45a8ff 49 {P0_6 , SPI_1, 2},
bogdanm 0:9b334a45a8ff 50 {P0_11, SPI_1, 2},
bogdanm 0:9b334a45a8ff 51 {P0_16, SPI_0, 2},
bogdanm 0:9b334a45a8ff 52 {P1_21, SPI_0, 3},
bogdanm 0:9b334a45a8ff 53 {NC , NC , 0}
bogdanm 0:9b334a45a8ff 54 };
bogdanm 0:9b334a45a8ff 55
bogdanm 0:9b334a45a8ff 56 static inline int ssp_disable(spi_t *obj);
bogdanm 0:9b334a45a8ff 57 static inline int ssp_enable(spi_t *obj);
bogdanm 0:9b334a45a8ff 58
bogdanm 0:9b334a45a8ff 59 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
bogdanm 0:9b334a45a8ff 60 // determine the SPI to use
bogdanm 0:9b334a45a8ff 61 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
bogdanm 0:9b334a45a8ff 62 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
bogdanm 0:9b334a45a8ff 63 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
bogdanm 0:9b334a45a8ff 64 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
bogdanm 0:9b334a45a8ff 65 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
bogdanm 0:9b334a45a8ff 66 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
bogdanm 0:9b334a45a8ff 67 obj->spi = (LPC_SSP_TypeDef*)pinmap_merge(spi_data, spi_cntl);
bogdanm 0:9b334a45a8ff 68 MBED_ASSERT((int)obj->spi != NC);
bogdanm 0:9b334a45a8ff 69
bogdanm 0:9b334a45a8ff 70 // enable power and clocking
bogdanm 0:9b334a45a8ff 71 switch ((int)obj->spi) {
bogdanm 0:9b334a45a8ff 72 case SPI_0: LPC_SC->PCONP |= 1 << 21; break;
bogdanm 0:9b334a45a8ff 73 case SPI_1: LPC_SC->PCONP |= 1 << 10; break;
bogdanm 0:9b334a45a8ff 74 }
bogdanm 0:9b334a45a8ff 75
bogdanm 0:9b334a45a8ff 76 // pin out the spi pins
bogdanm 0:9b334a45a8ff 77 pinmap_pinout(mosi, PinMap_SPI_MOSI);
bogdanm 0:9b334a45a8ff 78 pinmap_pinout(miso, PinMap_SPI_MISO);
bogdanm 0:9b334a45a8ff 79 pinmap_pinout(sclk, PinMap_SPI_SCLK);
bogdanm 0:9b334a45a8ff 80 if (ssel != NC) {
bogdanm 0:9b334a45a8ff 81 pinmap_pinout(ssel, PinMap_SPI_SSEL);
bogdanm 0:9b334a45a8ff 82 }
bogdanm 0:9b334a45a8ff 83 }
bogdanm 0:9b334a45a8ff 84
bogdanm 0:9b334a45a8ff 85 void spi_free(spi_t *obj) {}
bogdanm 0:9b334a45a8ff 86
bogdanm 0:9b334a45a8ff 87 void spi_format(spi_t *obj, int bits, int mode, int slave) {
bogdanm 0:9b334a45a8ff 88 MBED_ASSERT(((bits >= 4) && (bits <= 16)) && ((mode >= 0) && (mode <= 3)));
bogdanm 0:9b334a45a8ff 89 ssp_disable(obj);
bogdanm 0:9b334a45a8ff 90
bogdanm 0:9b334a45a8ff 91 int polarity = (mode & 0x2) ? 1 : 0;
bogdanm 0:9b334a45a8ff 92 int phase = (mode & 0x1) ? 1 : 0;
bogdanm 0:9b334a45a8ff 93
bogdanm 0:9b334a45a8ff 94 // set it up
bogdanm 0:9b334a45a8ff 95 int DSS = bits - 1; // DSS (data select size)
bogdanm 0:9b334a45a8ff 96 int SPO = (polarity) ? 1 : 0; // SPO - clock out polarity
bogdanm 0:9b334a45a8ff 97 int SPH = (phase) ? 1 : 0; // SPH - clock out phase
bogdanm 0:9b334a45a8ff 98
bogdanm 0:9b334a45a8ff 99 int FRF = 0; // FRF (frame format) = SPI
bogdanm 0:9b334a45a8ff 100 uint32_t tmp = obj->spi->CR0;
bogdanm 0:9b334a45a8ff 101 tmp &= ~(0xFFFF);
bogdanm 0:9b334a45a8ff 102 tmp |= DSS << 0
bogdanm 0:9b334a45a8ff 103 | FRF << 4
bogdanm 0:9b334a45a8ff 104 | SPO << 6
bogdanm 0:9b334a45a8ff 105 | SPH << 7;
bogdanm 0:9b334a45a8ff 106 obj->spi->CR0 = tmp;
bogdanm 0:9b334a45a8ff 107
bogdanm 0:9b334a45a8ff 108 tmp = obj->spi->CR1;
bogdanm 0:9b334a45a8ff 109 tmp &= ~(0xD);
bogdanm 0:9b334a45a8ff 110 tmp |= 0 << 0 // LBM - loop back mode - off
bogdanm 0:9b334a45a8ff 111 | ((slave) ? 1 : 0) << 2 // MS - master slave mode, 1 = slave
bogdanm 0:9b334a45a8ff 112 | 0 << 3; // SOD - slave output disable - na
bogdanm 0:9b334a45a8ff 113 obj->spi->CR1 = tmp;
bogdanm 0:9b334a45a8ff 114
bogdanm 0:9b334a45a8ff 115 ssp_enable(obj);
bogdanm 0:9b334a45a8ff 116 }
bogdanm 0:9b334a45a8ff 117
bogdanm 0:9b334a45a8ff 118 void spi_frequency(spi_t *obj, int hz) {
bogdanm 0:9b334a45a8ff 119 ssp_disable(obj);
bogdanm 0:9b334a45a8ff 120
bogdanm 0:9b334a45a8ff 121 // setup the spi clock diveder to /1
bogdanm 0:9b334a45a8ff 122 switch ((int)obj->spi) {
bogdanm 0:9b334a45a8ff 123 case SPI_0:
bogdanm 0:9b334a45a8ff 124 LPC_SC->PCLKSEL1 &= ~(3 << 10);
bogdanm 0:9b334a45a8ff 125 LPC_SC->PCLKSEL1 |= (1 << 10);
bogdanm 0:9b334a45a8ff 126 break;
bogdanm 0:9b334a45a8ff 127 case SPI_1:
bogdanm 0:9b334a45a8ff 128 LPC_SC->PCLKSEL0 &= ~(3 << 20);
bogdanm 0:9b334a45a8ff 129 LPC_SC->PCLKSEL0 |= (1 << 20);
bogdanm 0:9b334a45a8ff 130 break;
bogdanm 0:9b334a45a8ff 131 }
bogdanm 0:9b334a45a8ff 132
bogdanm 0:9b334a45a8ff 133 uint32_t PCLK = SystemCoreClock;
bogdanm 0:9b334a45a8ff 134
bogdanm 0:9b334a45a8ff 135 int prescaler;
bogdanm 0:9b334a45a8ff 136
bogdanm 0:9b334a45a8ff 137 for (prescaler = 2; prescaler <= 254; prescaler += 2) {
bogdanm 0:9b334a45a8ff 138 int prescale_hz = PCLK / prescaler;
bogdanm 0:9b334a45a8ff 139
bogdanm 0:9b334a45a8ff 140 // calculate the divider
bogdanm 0:9b334a45a8ff 141 int divider = floor(((float)prescale_hz / (float)hz) + 0.5f);
bogdanm 0:9b334a45a8ff 142
bogdanm 0:9b334a45a8ff 143 // check we can support the divider
bogdanm 0:9b334a45a8ff 144 if (divider < 256) {
bogdanm 0:9b334a45a8ff 145 // prescaler
bogdanm 0:9b334a45a8ff 146 obj->spi->CPSR = prescaler;
bogdanm 0:9b334a45a8ff 147
bogdanm 0:9b334a45a8ff 148 // divider
bogdanm 0:9b334a45a8ff 149 obj->spi->CR0 &= ~(0xFFFF << 8);
bogdanm 0:9b334a45a8ff 150 obj->spi->CR0 |= (divider - 1) << 8;
bogdanm 0:9b334a45a8ff 151 ssp_enable(obj);
bogdanm 0:9b334a45a8ff 152 return;
bogdanm 0:9b334a45a8ff 153 }
bogdanm 0:9b334a45a8ff 154 }
bogdanm 0:9b334a45a8ff 155 error("Couldn't setup requested SPI frequency");
bogdanm 0:9b334a45a8ff 156 }
bogdanm 0:9b334a45a8ff 157
bogdanm 0:9b334a45a8ff 158 static inline int ssp_disable(spi_t *obj) {
bogdanm 0:9b334a45a8ff 159 return obj->spi->CR1 &= ~(1 << 1);
bogdanm 0:9b334a45a8ff 160 }
bogdanm 0:9b334a45a8ff 161
bogdanm 0:9b334a45a8ff 162 static inline int ssp_enable(spi_t *obj) {
bogdanm 0:9b334a45a8ff 163 return obj->spi->CR1 |= (1 << 1);
bogdanm 0:9b334a45a8ff 164 }
bogdanm 0:9b334a45a8ff 165
bogdanm 0:9b334a45a8ff 166 static inline int ssp_readable(spi_t *obj) {
bogdanm 0:9b334a45a8ff 167 return obj->spi->SR & (1 << 2);
bogdanm 0:9b334a45a8ff 168 }
bogdanm 0:9b334a45a8ff 169
bogdanm 0:9b334a45a8ff 170 static inline int ssp_writeable(spi_t *obj) {
bogdanm 0:9b334a45a8ff 171 return obj->spi->SR & (1 << 1);
bogdanm 0:9b334a45a8ff 172 }
bogdanm 0:9b334a45a8ff 173
bogdanm 0:9b334a45a8ff 174 static inline void ssp_write(spi_t *obj, int value) {
bogdanm 0:9b334a45a8ff 175 while (!ssp_writeable(obj));
bogdanm 0:9b334a45a8ff 176 obj->spi->DR = value;
bogdanm 0:9b334a45a8ff 177 }
bogdanm 0:9b334a45a8ff 178
bogdanm 0:9b334a45a8ff 179 static inline int ssp_read(spi_t *obj) {
bogdanm 0:9b334a45a8ff 180 while (!ssp_readable(obj));
bogdanm 0:9b334a45a8ff 181 return obj->spi->DR;
bogdanm 0:9b334a45a8ff 182 }
bogdanm 0:9b334a45a8ff 183
bogdanm 0:9b334a45a8ff 184 static inline int ssp_busy(spi_t *obj) {
bogdanm 0:9b334a45a8ff 185 return (obj->spi->SR & (1 << 4)) ? (1) : (0);
bogdanm 0:9b334a45a8ff 186 }
bogdanm 0:9b334a45a8ff 187
bogdanm 0:9b334a45a8ff 188 int spi_master_write(spi_t *obj, int value) {
bogdanm 0:9b334a45a8ff 189 ssp_write(obj, value);
bogdanm 0:9b334a45a8ff 190 return ssp_read(obj);
bogdanm 0:9b334a45a8ff 191 }
bogdanm 0:9b334a45a8ff 192
bogdanm 0:9b334a45a8ff 193 int spi_slave_receive(spi_t *obj) {
bogdanm 0:9b334a45a8ff 194 return (ssp_readable(obj) && !ssp_busy(obj)) ? (1) : (0);
bogdanm 0:9b334a45a8ff 195 }
bogdanm 0:9b334a45a8ff 196
bogdanm 0:9b334a45a8ff 197 int spi_slave_read(spi_t *obj) {
bogdanm 0:9b334a45a8ff 198 return obj->spi->DR;
bogdanm 0:9b334a45a8ff 199 }
bogdanm 0:9b334a45a8ff 200
bogdanm 0:9b334a45a8ff 201 void spi_slave_write(spi_t *obj, int value) {
bogdanm 0:9b334a45a8ff 202 while (ssp_writeable(obj) == 0) ;
bogdanm 0:9b334a45a8ff 203 obj->spi->DR = value;
bogdanm 0:9b334a45a8ff 204 }
bogdanm 0:9b334a45a8ff 205
bogdanm 0:9b334a45a8ff 206 int spi_busy(spi_t *obj) {
bogdanm 0:9b334a45a8ff 207 return ssp_busy(obj);
bogdanm 0:9b334a45a8ff 208 }