Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

targets/TARGET_NXP/TARGET_LPC43XX/spi_api.c@0:f269e3021894, 2016-10-23 (annotated)

Committer:
elessair
Date:
Sun Oct 23 15:10:02 2016 +0000
Revision:
0:f269e3021894
Initial commit

Who changed what in which revision?

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elessair 0:f269e3021894 1 /* mbed Microcontroller Library
elessair 0:f269e3021894 2 * Copyright (c) 2006-2013 ARM Limited
elessair 0:f269e3021894 3 *
elessair 0:f269e3021894 4 * Licensed under the Apache License, Version 2.0 (the "License");
elessair 0:f269e3021894 5 * you may not use this file except in compliance with the License.
elessair 0:f269e3021894 6 * You may obtain a copy of the License at
elessair 0:f269e3021894 7 *
elessair 0:f269e3021894 8 * http://www.apache.org/licenses/LICENSE-2.0
elessair 0:f269e3021894 9 *
elessair 0:f269e3021894 10 * Unless required by applicable law or agreed to in writing, software
elessair 0:f269e3021894 11 * distributed under the License is distributed on an "AS IS" BASIS,
elessair 0:f269e3021894 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elessair 0:f269e3021894 13 * See the License for the specific language governing permissions and
elessair 0:f269e3021894 14 * limitations under the License.
elessair 0:f269e3021894 15 *
elessair 0:f269e3021894 16 * Ported to NXP LPC43XX by Micromint USA <support@micromint.com>
elessair 0:f269e3021894 17 */
elessair 0:f269e3021894 18 #include "mbed_assert.h"
elessair 0:f269e3021894 19 #include <math.h>
elessair 0:f269e3021894 20
elessair 0:f269e3021894 21 #include "spi_api.h"
elessair 0:f269e3021894 22 #include "cmsis.h"
elessair 0:f269e3021894 23 #include "pinmap.h"
elessair 0:f269e3021894 24 #include "mbed_error.h"
elessair 0:f269e3021894 25
elessair 0:f269e3021894 26 // SCU mode for SPI pins
elessair 0:f269e3021894 27 #define SCU_PINIO_SPI SCU_PINIO_FAST
elessair 0:f269e3021894 28
elessair 0:f269e3021894 29 static const PinMap PinMap_SPI_SCLK[] = {
elessair 0:f269e3021894 30 {P1_19, SPI_1, (SCU_PINIO_SPI | 1)},
elessair 0:f269e3021894 31 {P3_0, SPI_0, (SCU_PINIO_SPI | 4)},
elessair 0:f269e3021894 32 {P3_3, SPI_0, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 33 {PF_0, SPI_0, (SCU_PINIO_SPI | 0)},
elessair 0:f269e3021894 34 {PF_4, SPI_1, (SCU_PINIO_SPI | 0)},
elessair 0:f269e3021894 35 {NC, NC, 0}
elessair 0:f269e3021894 36 };
elessair 0:f269e3021894 37
elessair 0:f269e3021894 38 static const PinMap PinMap_SPI_MOSI[] = {
elessair 0:f269e3021894 39 {P0_1, SPI_1, (SCU_PINIO_SPI | 1)},
elessair 0:f269e3021894 40 {P1_2, SPI_0, (SCU_PINIO_SPI | 5)},
elessair 0:f269e3021894 41 {P1_4, SPI_1, (SCU_PINIO_SPI | 5)},
elessair 0:f269e3021894 42 {P3_7, SPI_0, (SCU_PINIO_SPI | 5)},
elessair 0:f269e3021894 43 {P3_8, SPI_0, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 44 {P9_2, SPI_0, (SCU_PINIO_SPI | 7)},
elessair 0:f269e3021894 45 {PF_3, SPI_0, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 46 {PF_7, SPI_1, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 47 {NC, NC, 0}
elessair 0:f269e3021894 48 };
elessair 0:f269e3021894 49
elessair 0:f269e3021894 50 static const PinMap PinMap_SPI_MISO[] = {
elessair 0:f269e3021894 51 {P0_0, SPI_1, (SCU_PINIO_SPI | 1)},
elessair 0:f269e3021894 52 {P1_1, SPI_0, (SCU_PINIO_SPI | 5)},
elessair 0:f269e3021894 53 {P1_3, SPI_1, (SCU_PINIO_SPI | 5)},
elessair 0:f269e3021894 54 {P3_6, SPI_0, (SCU_PINIO_SPI | 5)},
elessair 0:f269e3021894 55 {P3_7, SPI_0, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 56 {P9_1, SPI_0, (SCU_PINIO_SPI | 7)},
elessair 0:f269e3021894 57 {PF_2, SPI_0, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 58 {PF_6, SPI_1, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 59 {NC, NC, 0}
elessair 0:f269e3021894 60 };
elessair 0:f269e3021894 61
elessair 0:f269e3021894 62 static const PinMap PinMap_SPI_SSEL[] = {
elessair 0:f269e3021894 63 {P1_0, SPI_0, (SCU_PINIO_SPI | 5)},
elessair 0:f269e3021894 64 {P1_5, SPI_1, (SCU_PINIO_SPI | 5)},
elessair 0:f269e3021894 65 {P1_20, SPI_1, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 66 {P3_6, SPI_0, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 67 {P3_8, SPI_0, (SCU_PINIO_SPI | 5)},
elessair 0:f269e3021894 68 {P9_0, SPI_0, (SCU_PINIO_SPI | 7)},
elessair 0:f269e3021894 69 {PF_1, SPI_0, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 70 {PF_5, SPI_1, (SCU_PINIO_SPI | 2)},
elessair 0:f269e3021894 71 {NC, NC, 0}
elessair 0:f269e3021894 72 };
elessair 0:f269e3021894 73
elessair 0:f269e3021894 74 static inline int ssp_disable(spi_t *obj);
elessair 0:f269e3021894 75 static inline int ssp_enable(spi_t *obj);
elessair 0:f269e3021894 76
elessair 0:f269e3021894 77 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
elessair 0:f269e3021894 78 // determine the SPI to use
elessair 0:f269e3021894 79 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
elessair 0:f269e3021894 80 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
elessair 0:f269e3021894 81 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
elessair 0:f269e3021894 82 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
elessair 0:f269e3021894 83 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
elessair 0:f269e3021894 84 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
elessair 0:f269e3021894 85
elessair 0:f269e3021894 86 obj->spi = (LPC_SSP_T*)pinmap_merge(spi_data, spi_cntl);
elessair 0:f269e3021894 87 MBED_ASSERT((int)obj->spi != NC);
elessair 0:f269e3021894 88
elessair 0:f269e3021894 89 // enable clocking
elessair 0:f269e3021894 90 switch ((int)obj->spi) {
elessair 0:f269e3021894 91 case SPI_0: LPC_CGU->BASE_CLK[CLK_BASE_SSP0] = (1 << 11) | (CLKIN_MAINPLL << 24); break;
elessair 0:f269e3021894 92 case SPI_1: LPC_CGU->BASE_CLK[CLK_BASE_SSP1] = (1 << 11) | (CLKIN_MAINPLL << 24); break;
elessair 0:f269e3021894 93 }
elessair 0:f269e3021894 94
elessair 0:f269e3021894 95 // pin out the spi pins
elessair 0:f269e3021894 96 pinmap_pinout(mosi, PinMap_SPI_MOSI);
elessair 0:f269e3021894 97 pinmap_pinout(miso, PinMap_SPI_MISO);
elessair 0:f269e3021894 98 pinmap_pinout(sclk, PinMap_SPI_SCLK);
elessair 0:f269e3021894 99 if (ssel != NC) {
elessair 0:f269e3021894 100 pinmap_pinout(ssel, PinMap_SPI_SSEL);
elessair 0:f269e3021894 101 }
elessair 0:f269e3021894 102 }
elessair 0:f269e3021894 103
elessair 0:f269e3021894 104 void spi_free(spi_t *obj) {}
elessair 0:f269e3021894 105
elessair 0:f269e3021894 106 void spi_format(spi_t *obj, int bits, int mode, int slave) {
elessair 0:f269e3021894 107 MBED_ASSERT(((bits >= 4) && (bits <= 16)) || ((mode >= 0) && (mode <= 3)));
elessair 0:f269e3021894 108 ssp_disable(obj);
elessair 0:f269e3021894 109
elessair 0:f269e3021894 110 int polarity = (mode & 0x2) ? 1 : 0;
elessair 0:f269e3021894 111 int phase = (mode & 0x1) ? 1 : 0;
elessair 0:f269e3021894 112
elessair 0:f269e3021894 113 // set it up
elessair 0:f269e3021894 114 int DSS = bits - 1; // DSS (data select size)
elessair 0:f269e3021894 115 int SPO = (polarity) ? 1 : 0; // SPO - clock out polarity
elessair 0:f269e3021894 116 int SPH = (phase) ? 1 : 0; // SPH - clock out phase
elessair 0:f269e3021894 117
elessair 0:f269e3021894 118 int FRF = 0; // FRF (frame format) = SPI
elessair 0:f269e3021894 119 uint32_t tmp = obj->spi->CR0;
elessair 0:f269e3021894 120 tmp &= ~(0xFFFF);
elessair 0:f269e3021894 121 tmp |= DSS << 0
elessair 0:f269e3021894 122 | FRF << 4
elessair 0:f269e3021894 123 | SPO << 6
elessair 0:f269e3021894 124 | SPH << 7;
elessair 0:f269e3021894 125 obj->spi->CR0 = tmp;
elessair 0:f269e3021894 126
elessair 0:f269e3021894 127 tmp = obj->spi->CR1;
elessair 0:f269e3021894 128 tmp &= ~(0xD);
elessair 0:f269e3021894 129 tmp |= 0 << 0 // LBM - loop back mode - off
elessair 0:f269e3021894 130 | ((slave) ? 1 : 0) << 2 // MS - master slave mode, 1 = slave
elessair 0:f269e3021894 131 | 0 << 3; // SOD - slave output disable - na
elessair 0:f269e3021894 132 obj->spi->CR1 = tmp;
elessair 0:f269e3021894 133 ssp_enable(obj);
elessair 0:f269e3021894 134 }
elessair 0:f269e3021894 135
elessair 0:f269e3021894 136 void spi_frequency(spi_t *obj, int hz) {
elessair 0:f269e3021894 137 ssp_disable(obj);
elessair 0:f269e3021894 138
elessair 0:f269e3021894 139 uint32_t PCLK = SystemCoreClock;
elessair 0:f269e3021894 140
elessair 0:f269e3021894 141 int prescaler;
elessair 0:f269e3021894 142
elessair 0:f269e3021894 143 for (prescaler = 2; prescaler <= 254; prescaler += 2) {
elessair 0:f269e3021894 144 int prescale_hz = PCLK / prescaler;
elessair 0:f269e3021894 145
elessair 0:f269e3021894 146 // calculate the divider
elessair 0:f269e3021894 147 int divider = floor(((float)prescale_hz / (float)hz) + 0.5f);
elessair 0:f269e3021894 148
elessair 0:f269e3021894 149 // check we can support the divider
elessair 0:f269e3021894 150 if (divider < 256) {
elessair 0:f269e3021894 151 // prescaler
elessair 0:f269e3021894 152 obj->spi->CPSR = prescaler;
elessair 0:f269e3021894 153
elessair 0:f269e3021894 154 // divider
elessair 0:f269e3021894 155 obj->spi->CR0 &= ~(0xFFFF << 8);
elessair 0:f269e3021894 156 obj->spi->CR0 |= (divider - 1) << 8;
elessair 0:f269e3021894 157 ssp_enable(obj);
elessair 0:f269e3021894 158 return;
elessair 0:f269e3021894 159 }
elessair 0:f269e3021894 160 }
elessair 0:f269e3021894 161 error("Couldn't setup requested SPI frequency");
elessair 0:f269e3021894 162 }
elessair 0:f269e3021894 163
elessair 0:f269e3021894 164 static inline int ssp_disable(spi_t *obj) {
elessair 0:f269e3021894 165 return obj->spi->CR1 &= ~(1 << 1);
elessair 0:f269e3021894 166 }
elessair 0:f269e3021894 167
elessair 0:f269e3021894 168 static inline int ssp_enable(spi_t *obj) {
elessair 0:f269e3021894 169 return obj->spi->CR1 |= (1 << 1);
elessair 0:f269e3021894 170 }
elessair 0:f269e3021894 171
elessair 0:f269e3021894 172 static inline int ssp_readable(spi_t *obj) {
elessair 0:f269e3021894 173 return obj->spi->SR & (1 << 2);
elessair 0:f269e3021894 174 }
elessair 0:f269e3021894 175
elessair 0:f269e3021894 176 static inline int ssp_writeable(spi_t *obj) {
elessair 0:f269e3021894 177 return obj->spi->SR & (1 << 1);
elessair 0:f269e3021894 178 }
elessair 0:f269e3021894 179
elessair 0:f269e3021894 180 static inline void ssp_write(spi_t *obj, int value) {
elessair 0:f269e3021894 181 while (!ssp_writeable(obj));
elessair 0:f269e3021894 182 obj->spi->DR = value;
elessair 0:f269e3021894 183 }
elessair 0:f269e3021894 184
elessair 0:f269e3021894 185 static inline int ssp_read(spi_t *obj) {
elessair 0:f269e3021894 186 while (!ssp_readable(obj));
elessair 0:f269e3021894 187 return obj->spi->DR;
elessair 0:f269e3021894 188 }
elessair 0:f269e3021894 189
elessair 0:f269e3021894 190 static inline int ssp_busy(spi_t *obj) {
elessair 0:f269e3021894 191 return (obj->spi->SR & (1 << 4)) ? (1) : (0);
elessair 0:f269e3021894 192 }
elessair 0:f269e3021894 193
elessair 0:f269e3021894 194 int spi_master_write(spi_t *obj, int value) {
elessair 0:f269e3021894 195 ssp_write(obj, value);
elessair 0:f269e3021894 196 return ssp_read(obj);
elessair 0:f269e3021894 197 }
elessair 0:f269e3021894 198
elessair 0:f269e3021894 199 int spi_slave_receive(spi_t *obj) {
elessair 0:f269e3021894 200 return (ssp_readable(obj) && !ssp_busy(obj)) ? (1) : (0);
elessair 0:f269e3021894 201 }
elessair 0:f269e3021894 202
elessair 0:f269e3021894 203 int spi_slave_read(spi_t *obj) {
elessair 0:f269e3021894 204 return obj->spi->DR;
elessair 0:f269e3021894 205 }
elessair 0:f269e3021894 206
elessair 0:f269e3021894 207 void spi_slave_write(spi_t *obj, int value) {
elessair 0:f269e3021894 208 while (ssp_writeable(obj) == 0) ;
elessair 0:f269e3021894 209 obj->spi->DR = value;
elessair 0:f269e3021894 210 }
elessair 0:f269e3021894 211
elessair 0:f269e3021894 212 int spi_busy(spi_t *obj) {
elessair 0:f269e3021894 213 return ssp_busy(obj);
elessair 0:f269e3021894 214 }