Umar Naeem / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed-dev by Umar Naeem

targets/TARGET_NXP/TARGET_LPC13XX/spi_api.c@165:2dd56e6daeec, 2017-05-23 (annotated)

Committer:
ranaumarnaeem
Date:
Tue May 23 12:54:50 2017 +0000
Revision:
165:2dd56e6daeec
Parent:
149:156823d33999 
jhjg

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /* mbed Microcontroller Library
<> 144:ef7eb2e8f9f7 2 * Copyright (c) 2006-2013 ARM Limited
<> 144:ef7eb2e8f9f7 3 *
<> 144:ef7eb2e8f9f7 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 144:ef7eb2e8f9f7 5 * you may not use this file except in compliance with the License.
<> 144:ef7eb2e8f9f7 6 * You may obtain a copy of the License at
<> 144:ef7eb2e8f9f7 7 *
<> 144:ef7eb2e8f9f7 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 144:ef7eb2e8f9f7 9 *
<> 144:ef7eb2e8f9f7 10 * Unless required by applicable law or agreed to in writing, software
<> 144:ef7eb2e8f9f7 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 144:ef7eb2e8f9f7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 144:ef7eb2e8f9f7 13 * See the License for the specific language governing permissions and
<> 144:ef7eb2e8f9f7 14 * limitations under the License.
<> 144:ef7eb2e8f9f7 15 */
<> 144:ef7eb2e8f9f7 16 #include "mbed_assert.h"
<> 144:ef7eb2e8f9f7 17 #include <math.h>
<> 144:ef7eb2e8f9f7 18 #include "spi_api.h"
<> 144:ef7eb2e8f9f7 19 #include "cmsis.h"
<> 144:ef7eb2e8f9f7 20 #include "pinmap.h"
<> 144:ef7eb2e8f9f7 21 #include "mbed_error.h"
<> 144:ef7eb2e8f9f7 22
<> 144:ef7eb2e8f9f7 23 static const PinMap PinMap_SPI_SCLK[] = {
<> 144:ef7eb2e8f9f7 24 {P0_6 , SPI_0, 0x02},
<> 144:ef7eb2e8f9f7 25 {P0_10, SPI_0, 0x02},
<> 144:ef7eb2e8f9f7 26 {P1_29, SPI_0, 0x01},
<> 144:ef7eb2e8f9f7 27 {P1_15, SPI_1, 0x03},
<> 144:ef7eb2e8f9f7 28 {P1_20, SPI_1, 0x02},
<> 144:ef7eb2e8f9f7 29 {NC , NC , 0}
<> 144:ef7eb2e8f9f7 30 };
<> 144:ef7eb2e8f9f7 31
<> 144:ef7eb2e8f9f7 32 static const PinMap PinMap_SPI_MOSI[] = {
<> 144:ef7eb2e8f9f7 33 {P0_9 , SPI_0, 0x01},
<> 144:ef7eb2e8f9f7 34 {P0_21, SPI_1, 0x02},
<> 144:ef7eb2e8f9f7 35 {P1_22, SPI_1, 0x02},
<> 144:ef7eb2e8f9f7 36 {NC , NC , 0}
<> 144:ef7eb2e8f9f7 37 };
<> 144:ef7eb2e8f9f7 38
<> 144:ef7eb2e8f9f7 39 static const PinMap PinMap_SPI_MISO[] = {
<> 144:ef7eb2e8f9f7 40 {P0_8 , SPI_0, 0x01},
<> 144:ef7eb2e8f9f7 41 {P0_22, SPI_1, 0x03},
<> 144:ef7eb2e8f9f7 42 {P1_21, SPI_1, 0x02},
<> 144:ef7eb2e8f9f7 43 {NC , NC , 0}
<> 144:ef7eb2e8f9f7 44 };
<> 144:ef7eb2e8f9f7 45
<> 144:ef7eb2e8f9f7 46 static const PinMap PinMap_SPI_SSEL[] = {
<> 144:ef7eb2e8f9f7 47 {P0_2 , SPI_0, 0x01},
<> 144:ef7eb2e8f9f7 48 {P1_19, SPI_1, 0x02},
<> 144:ef7eb2e8f9f7 49 {P1_23, SPI_1, 0x02},
<> 144:ef7eb2e8f9f7 50 {NC , NC , 0}
<> 144:ef7eb2e8f9f7 51 };
<> 144:ef7eb2e8f9f7 52
<> 144:ef7eb2e8f9f7 53 static inline int ssp_disable(spi_t *obj);
<> 144:ef7eb2e8f9f7 54 static inline int ssp_enable(spi_t *obj);
<> 144:ef7eb2e8f9f7 55
<> 144:ef7eb2e8f9f7 56 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
<> 144:ef7eb2e8f9f7 57 // determine the SPI to use
<> 144:ef7eb2e8f9f7 58 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
<> 144:ef7eb2e8f9f7 59 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
<> 144:ef7eb2e8f9f7 60 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
<> 144:ef7eb2e8f9f7 61 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
<> 144:ef7eb2e8f9f7 62 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
<> 144:ef7eb2e8f9f7 63 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
<> 144:ef7eb2e8f9f7 64
<> 144:ef7eb2e8f9f7 65 obj->spi = (LPC_SSPx_Type*)pinmap_merge(spi_data, spi_cntl);
<> 144:ef7eb2e8f9f7 66 MBED_ASSERT((int)obj->spi != NC);
<> 144:ef7eb2e8f9f7 67
<> 144:ef7eb2e8f9f7 68 // enable power and clocking
<> 144:ef7eb2e8f9f7 69 switch ((int)obj->spi) {
<> 144:ef7eb2e8f9f7 70 case SPI_0:
<> 144:ef7eb2e8f9f7 71 LPC_SYSCON->SYSAHBCLKCTRL |= 1 << 11;
<> 144:ef7eb2e8f9f7 72 LPC_SYSCON->SSP0CLKDIV = 0x01;
<> 144:ef7eb2e8f9f7 73 LPC_SYSCON->PRESETCTRL |= 1 << 0;
<> 144:ef7eb2e8f9f7 74 break;
<> 144:ef7eb2e8f9f7 75 case SPI_1:
<> 144:ef7eb2e8f9f7 76 LPC_SYSCON->SYSAHBCLKCTRL |= 1 << 18;
<> 144:ef7eb2e8f9f7 77 LPC_SYSCON->SSP1CLKDIV = 0x01;
<> 144:ef7eb2e8f9f7 78 LPC_SYSCON->PRESETCTRL |= 1 << 2;
<> 144:ef7eb2e8f9f7 79 break;
<> 144:ef7eb2e8f9f7 80 }
<> 144:ef7eb2e8f9f7 81
<> 144:ef7eb2e8f9f7 82 // pin out the spi pins
<> 144:ef7eb2e8f9f7 83 pinmap_pinout(mosi, PinMap_SPI_MOSI);
<> 144:ef7eb2e8f9f7 84 pinmap_pinout(miso, PinMap_SPI_MISO);
<> 144:ef7eb2e8f9f7 85 pinmap_pinout(sclk, PinMap_SPI_SCLK);
<> 144:ef7eb2e8f9f7 86 if (ssel != NC) {
<> 144:ef7eb2e8f9f7 87 pinmap_pinout(ssel, PinMap_SPI_SSEL);
<> 144:ef7eb2e8f9f7 88 }
<> 144:ef7eb2e8f9f7 89 }
<> 144:ef7eb2e8f9f7 90
<> 144:ef7eb2e8f9f7 91 void spi_free(spi_t *obj) {}
<> 144:ef7eb2e8f9f7 92
<> 144:ef7eb2e8f9f7 93 void spi_format(spi_t *obj, int bits, int mode, int slave) {
<> 144:ef7eb2e8f9f7 94 ssp_disable(obj);
<> 144:ef7eb2e8f9f7 95 MBED_ASSERT((bits >= 4 && bits <= 16) || (mode >= 0 && mode <= 3));
<> 144:ef7eb2e8f9f7 96
<> 144:ef7eb2e8f9f7 97 int polarity = (mode & 0x2) ? 1 : 0;
<> 144:ef7eb2e8f9f7 98 int phase = (mode & 0x1) ? 1 : 0;
<> 144:ef7eb2e8f9f7 99
<> 144:ef7eb2e8f9f7 100 // set it up
<> 144:ef7eb2e8f9f7 101 int DSS = bits - 1; // DSS (data select size)
<> 144:ef7eb2e8f9f7 102 int SPO = (polarity) ? 1 : 0; // SPO - clock out polarity
<> 144:ef7eb2e8f9f7 103 int SPH = (phase) ? 1 : 0; // SPH - clock out phase
<> 144:ef7eb2e8f9f7 104
<> 144:ef7eb2e8f9f7 105 int FRF = 0; // FRF (frame format) = SPI
<> 144:ef7eb2e8f9f7 106 uint32_t tmp = obj->spi->CR0;
<> 144:ef7eb2e8f9f7 107 tmp &= ~(0xFFFF);
<> 144:ef7eb2e8f9f7 108 tmp |= DSS << 0
<> 144:ef7eb2e8f9f7 109 | FRF << 4
<> 144:ef7eb2e8f9f7 110 | SPO << 6
<> 144:ef7eb2e8f9f7 111 | SPH << 7;
<> 144:ef7eb2e8f9f7 112 obj->spi->CR0 = tmp;
<> 144:ef7eb2e8f9f7 113
<> 144:ef7eb2e8f9f7 114 tmp = obj->spi->CR1;
<> 144:ef7eb2e8f9f7 115 tmp &= ~(0xD);
<> 144:ef7eb2e8f9f7 116 tmp |= 0 << 0 // LBM - loop back mode - off
<> 144:ef7eb2e8f9f7 117 | ((slave) ? 1 : 0) << 2 // MS - master slave mode, 1 = slave
<> 144:ef7eb2e8f9f7 118 | 0 << 3; // SOD - slave output disable - na
<> 144:ef7eb2e8f9f7 119 obj->spi->CR1 = tmp;
<> 144:ef7eb2e8f9f7 120
<> 144:ef7eb2e8f9f7 121 ssp_enable(obj);
<> 144:ef7eb2e8f9f7 122 }
<> 144:ef7eb2e8f9f7 123
<> 144:ef7eb2e8f9f7 124 void spi_frequency(spi_t *obj, int hz) {
<> 144:ef7eb2e8f9f7 125 ssp_disable(obj);
<> 144:ef7eb2e8f9f7 126
<> 144:ef7eb2e8f9f7 127 uint32_t PCLK = SystemCoreClock;
<> 144:ef7eb2e8f9f7 128
<> 144:ef7eb2e8f9f7 129 int prescaler;
<> 144:ef7eb2e8f9f7 130
<> 144:ef7eb2e8f9f7 131 for (prescaler = 2; prescaler <= 254; prescaler += 2) {
<> 144:ef7eb2e8f9f7 132 int prescale_hz = PCLK / prescaler;
<> 144:ef7eb2e8f9f7 133
<> 144:ef7eb2e8f9f7 134 // calculate the divider
<> 144:ef7eb2e8f9f7 135 int divider = floor(((float)prescale_hz / (float)hz) + 0.5f);
<> 144:ef7eb2e8f9f7 136
<> 144:ef7eb2e8f9f7 137 // check we can support the divider
<> 144:ef7eb2e8f9f7 138 if (divider < 256) {
<> 144:ef7eb2e8f9f7 139 // prescaler
<> 144:ef7eb2e8f9f7 140 obj->spi->CPSR = prescaler;
<> 144:ef7eb2e8f9f7 141
<> 144:ef7eb2e8f9f7 142 // divider
<> 144:ef7eb2e8f9f7 143 obj->spi->CR0 &= ~(0xFFFF << 8);
<> 144:ef7eb2e8f9f7 144 obj->spi->CR0 |= (divider - 1) << 8;
<> 144:ef7eb2e8f9f7 145 ssp_enable(obj);
<> 144:ef7eb2e8f9f7 146 return;
<> 144:ef7eb2e8f9f7 147 }
<> 144:ef7eb2e8f9f7 148 }
<> 144:ef7eb2e8f9f7 149 error("Couldn't setup requested SPI frequency");
<> 144:ef7eb2e8f9f7 150 }
<> 144:ef7eb2e8f9f7 151
<> 144:ef7eb2e8f9f7 152 static inline int ssp_disable(spi_t *obj) {
<> 144:ef7eb2e8f9f7 153 return obj->spi->CR1 &= ~(1 << 1);
<> 144:ef7eb2e8f9f7 154 }
<> 144:ef7eb2e8f9f7 155
<> 144:ef7eb2e8f9f7 156 static inline int ssp_enable(spi_t *obj) {
<> 144:ef7eb2e8f9f7 157 return obj->spi->CR1 |= (1 << 1);
<> 144:ef7eb2e8f9f7 158 }
<> 144:ef7eb2e8f9f7 159
<> 144:ef7eb2e8f9f7 160 static inline int ssp_readable(spi_t *obj) {
<> 144:ef7eb2e8f9f7 161 return obj->spi->SR & (1 << 2);
<> 144:ef7eb2e8f9f7 162 }
<> 144:ef7eb2e8f9f7 163
<> 144:ef7eb2e8f9f7 164 static inline int ssp_writeable(spi_t *obj) {
<> 144:ef7eb2e8f9f7 165 return obj->spi->SR & (1 << 1);
<> 144:ef7eb2e8f9f7 166 }
<> 144:ef7eb2e8f9f7 167
<> 144:ef7eb2e8f9f7 168 static inline void ssp_write(spi_t *obj, int value) {
<> 144:ef7eb2e8f9f7 169 while (!ssp_writeable(obj));
<> 144:ef7eb2e8f9f7 170 obj->spi->DR = value;
<> 144:ef7eb2e8f9f7 171 }
<> 144:ef7eb2e8f9f7 172
<> 144:ef7eb2e8f9f7 173 static inline int ssp_read(spi_t *obj) {
<> 144:ef7eb2e8f9f7 174 while (!ssp_readable(obj));
<> 144:ef7eb2e8f9f7 175 return obj->spi->DR;
<> 144:ef7eb2e8f9f7 176 }
<> 144:ef7eb2e8f9f7 177
<> 144:ef7eb2e8f9f7 178 static inline int ssp_busy(spi_t *obj) {
<> 144:ef7eb2e8f9f7 179 return (obj->spi->SR & (1 << 4)) ? (1) : (0);
<> 144:ef7eb2e8f9f7 180 }
<> 144:ef7eb2e8f9f7 181
<> 144:ef7eb2e8f9f7 182 int spi_master_write(spi_t *obj, int value) {
<> 144:ef7eb2e8f9f7 183 ssp_write(obj, value);
<> 144:ef7eb2e8f9f7 184 return ssp_read(obj);
<> 144:ef7eb2e8f9f7 185 }
<> 144:ef7eb2e8f9f7 186
<> 144:ef7eb2e8f9f7 187 int spi_slave_receive(spi_t *obj) {
<> 144:ef7eb2e8f9f7 188 return (ssp_readable(obj) && !ssp_busy(obj)) ? (1) : (0);
<> 144:ef7eb2e8f9f7 189 }
<> 144:ef7eb2e8f9f7 190
<> 144:ef7eb2e8f9f7 191 int spi_slave_read(spi_t *obj) {
<> 144:ef7eb2e8f9f7 192 return obj->spi->DR;
<> 144:ef7eb2e8f9f7 193 }
<> 144:ef7eb2e8f9f7 194
<> 144:ef7eb2e8f9f7 195 void spi_slave_write(spi_t *obj, int value) {
<> 144:ef7eb2e8f9f7 196 while (ssp_writeable(obj) == 0) ;
<> 144:ef7eb2e8f9f7 197 obj->spi->DR = value;
<> 144:ef7eb2e8f9f7 198 }
<> 144:ef7eb2e8f9f7 199
<> 144:ef7eb2e8f9f7 200 int spi_busy(spi_t *obj) {
<> 144:ef7eb2e8f9f7 201 return ssp_busy(obj);
<> 144:ef7eb2e8f9f7 202 }