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mbed SDK library sources

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Development branch of the mbed library sources. This library is kept in synch with the latest changes from the mbed SDK and it is not guaranteed to work.

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The official Mbed 2 C/C++ SDK provides the software platform and libraries to build your applications.

Last commit 20 Feb 2019 by mbed official

targets/hal/TARGET_NXP/TARGET_LPC11XX_11CXX/spi_api.c@30:91c1d09ada54, 2013-09-25 (annotated)

Committer:
mbed_official
Date:
Wed Sep 25 10:30:04 2013 +0100
Revision:
30:91c1d09ada54
Child:
32:4742f6c694e8
Synchronized with git revision 8f57c1e84759991fa81ede0da2b4aabe8530fa09

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 30:91c1d09ada54 1 /* mbed Microcontroller Library
mbed_official 30:91c1d09ada54 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 30:91c1d09ada54 3 *
mbed_official 30:91c1d09ada54 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 30:91c1d09ada54 5 * you may not use this file except in compliance with the License.
mbed_official 30:91c1d09ada54 6 * You may obtain a copy of the License at
mbed_official 30:91c1d09ada54 7 *
mbed_official 30:91c1d09ada54 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 30:91c1d09ada54 9 *
mbed_official 30:91c1d09ada54 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 30:91c1d09ada54 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 30:91c1d09ada54 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 30:91c1d09ada54 13 * See the License for the specific language governing permissions and
mbed_official 30:91c1d09ada54 14 * limitations under the License.
mbed_official 30:91c1d09ada54 15 */
mbed_official 30:91c1d09ada54 16 #include <math.h>
mbed_official 30:91c1d09ada54 17 #include "spi_api.h"
mbed_official 30:91c1d09ada54 18 #include "cmsis.h"
mbed_official 30:91c1d09ada54 19 #include "pinmap.h"
mbed_official 30:91c1d09ada54 20 #include "error.h"
mbed_official 30:91c1d09ada54 21
mbed_official 30:91c1d09ada54 22 #include "spi_pinmap.h"
mbed_official 30:91c1d09ada54 23
mbed_official 30:91c1d09ada54 24 static inline int ssp_disable(spi_t *obj);
mbed_official 30:91c1d09ada54 25 static inline int ssp_enable(spi_t *obj);
mbed_official 30:91c1d09ada54 26
mbed_official 30:91c1d09ada54 27 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
mbed_official 30:91c1d09ada54 28 // determine the SPI to use
mbed_official 30:91c1d09ada54 29 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
mbed_official 30:91c1d09ada54 30 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
mbed_official 30:91c1d09ada54 31 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
mbed_official 30:91c1d09ada54 32 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
mbed_official 30:91c1d09ada54 33 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
mbed_official 30:91c1d09ada54 34 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
mbed_official 30:91c1d09ada54 35
mbed_official 30:91c1d09ada54 36 obj->spi = (LPC_SSP_TypeDef*)pinmap_merge(spi_data, spi_cntl);
mbed_official 30:91c1d09ada54 37
mbed_official 30:91c1d09ada54 38 if ((int)obj->spi == NC) {
mbed_official 30:91c1d09ada54 39 error("SPI pinout mapping failed");
mbed_official 30:91c1d09ada54 40 }
mbed_official 30:91c1d09ada54 41
mbed_official 30:91c1d09ada54 42 // enable power and clocking
mbed_official 30:91c1d09ada54 43 switch ((int)obj->spi) {
mbed_official 30:91c1d09ada54 44 case SPI_0:
mbed_official 30:91c1d09ada54 45 LPC_SYSCON->SYSAHBCLKCTRL |= 1 << 11;
mbed_official 30:91c1d09ada54 46 LPC_SYSCON->SSP0CLKDIV = 0x01;
mbed_official 30:91c1d09ada54 47 LPC_SYSCON->PRESETCTRL |= 1 << 0;
mbed_official 30:91c1d09ada54 48 break;
mbed_official 30:91c1d09ada54 49 case SPI_1:
mbed_official 30:91c1d09ada54 50 LPC_SYSCON->SYSAHBCLKCTRL |= 1 << 18;
mbed_official 30:91c1d09ada54 51 LPC_SYSCON->SSP1CLKDIV = 0x01;
mbed_official 30:91c1d09ada54 52 LPC_SYSCON->PRESETCTRL |= 1 << 2;
mbed_official 30:91c1d09ada54 53 break;
mbed_official 30:91c1d09ada54 54 }
mbed_official 30:91c1d09ada54 55
mbed_official 30:91c1d09ada54 56 // set default format and frequency
mbed_official 30:91c1d09ada54 57 if (ssel == NC) {
mbed_official 30:91c1d09ada54 58 spi_format(obj, 8, 0, 0); // 8 bits, mode 0, master
mbed_official 30:91c1d09ada54 59 } else {
mbed_official 30:91c1d09ada54 60 spi_format(obj, 8, 0, 1); // 8 bits, mode 0, slave
mbed_official 30:91c1d09ada54 61 }
mbed_official 30:91c1d09ada54 62 spi_frequency(obj, 1000000);
mbed_official 30:91c1d09ada54 63
mbed_official 30:91c1d09ada54 64 // enable the ssp channel
mbed_official 30:91c1d09ada54 65 ssp_enable(obj);
mbed_official 30:91c1d09ada54 66
mbed_official 30:91c1d09ada54 67 // pin out the spi pins
mbed_official 30:91c1d09ada54 68 pinmap_pinout(mosi, PinMap_SPI_MOSI);
mbed_official 30:91c1d09ada54 69 pinmap_pinout(miso, PinMap_SPI_MISO);
mbed_official 30:91c1d09ada54 70 pinmap_pinout(sclk, PinMap_SPI_SCLK);
mbed_official 30:91c1d09ada54 71 if (ssel != NC) {
mbed_official 30:91c1d09ada54 72 pinmap_pinout(ssel, PinMap_SPI_SSEL);
mbed_official 30:91c1d09ada54 73 }
mbed_official 30:91c1d09ada54 74 }
mbed_official 30:91c1d09ada54 75
mbed_official 30:91c1d09ada54 76 void spi_free(spi_t *obj) {}
mbed_official 30:91c1d09ada54 77
mbed_official 30:91c1d09ada54 78 void spi_format(spi_t *obj, int bits, int mode, int slave) {
mbed_official 30:91c1d09ada54 79 ssp_disable(obj);
mbed_official 30:91c1d09ada54 80
mbed_official 30:91c1d09ada54 81 if (!(bits >= 4 && bits <= 16) || !(mode >= 0 && mode <= 3)) {
mbed_official 30:91c1d09ada54 82 error("SPI format error");
mbed_official 30:91c1d09ada54 83 }
mbed_official 30:91c1d09ada54 84
mbed_official 30:91c1d09ada54 85 int polarity = (mode & 0x2) ? 1 : 0;
mbed_official 30:91c1d09ada54 86 int phase = (mode & 0x1) ? 1 : 0;
mbed_official 30:91c1d09ada54 87
mbed_official 30:91c1d09ada54 88 // set it up
mbed_official 30:91c1d09ada54 89 int DSS = bits - 1; // DSS (data select size)
mbed_official 30:91c1d09ada54 90 int SPO = (polarity) ? 1 : 0; // SPO - clock out polarity
mbed_official 30:91c1d09ada54 91 int SPH = (phase) ? 1 : 0; // SPH - clock out phase
mbed_official 30:91c1d09ada54 92
mbed_official 30:91c1d09ada54 93 int FRF = 0; // FRF (frame format) = SPI
mbed_official 30:91c1d09ada54 94 uint32_t tmp = obj->spi->CR0;
mbed_official 30:91c1d09ada54 95 tmp &= ~(0xFFFF);
mbed_official 30:91c1d09ada54 96 tmp |= DSS << 0
mbed_official 30:91c1d09ada54 97 | FRF << 4
mbed_official 30:91c1d09ada54 98 | SPO << 6
mbed_official 30:91c1d09ada54 99 | SPH << 7;
mbed_official 30:91c1d09ada54 100 obj->spi->CR0 = tmp;
mbed_official 30:91c1d09ada54 101
mbed_official 30:91c1d09ada54 102 tmp = obj->spi->CR1;
mbed_official 30:91c1d09ada54 103 tmp &= ~(0xD);
mbed_official 30:91c1d09ada54 104 tmp |= 0 << 0 // LBM - loop back mode - off
mbed_official 30:91c1d09ada54 105 | ((slave) ? 1 : 0) << 2 // MS - master slave mode, 1 = slave
mbed_official 30:91c1d09ada54 106 | 0 << 3; // SOD - slave output disable - na
mbed_official 30:91c1d09ada54 107 obj->spi->CR1 = tmp;
mbed_official 30:91c1d09ada54 108
mbed_official 30:91c1d09ada54 109 ssp_enable(obj);
mbed_official 30:91c1d09ada54 110 }
mbed_official 30:91c1d09ada54 111
mbed_official 30:91c1d09ada54 112 void spi_frequency(spi_t *obj, int hz) {
mbed_official 30:91c1d09ada54 113 ssp_disable(obj);
mbed_official 30:91c1d09ada54 114
mbed_official 30:91c1d09ada54 115 uint32_t PCLK = SystemCoreClock;
mbed_official 30:91c1d09ada54 116
mbed_official 30:91c1d09ada54 117 int prescaler;
mbed_official 30:91c1d09ada54 118
mbed_official 30:91c1d09ada54 119 for (prescaler = 2; prescaler <= 254; prescaler += 2) {
mbed_official 30:91c1d09ada54 120 int prescale_hz = PCLK / prescaler;
mbed_official 30:91c1d09ada54 121
mbed_official 30:91c1d09ada54 122 // calculate the divider
mbed_official 30:91c1d09ada54 123 int divider = floor(((float)prescale_hz / (float)hz) + 0.5f);
mbed_official 30:91c1d09ada54 124
mbed_official 30:91c1d09ada54 125 // check we can support the divider
mbed_official 30:91c1d09ada54 126 if (divider < 256) {
mbed_official 30:91c1d09ada54 127 // prescaler
mbed_official 30:91c1d09ada54 128 obj->spi->CPSR = prescaler;
mbed_official 30:91c1d09ada54 129
mbed_official 30:91c1d09ada54 130 // divider
mbed_official 30:91c1d09ada54 131 obj->spi->CR0 &= ~(0xFFFF << 8);
mbed_official 30:91c1d09ada54 132 obj->spi->CR0 |= (divider - 1) << 8;
mbed_official 30:91c1d09ada54 133 ssp_enable(obj);
mbed_official 30:91c1d09ada54 134 return;
mbed_official 30:91c1d09ada54 135 }
mbed_official 30:91c1d09ada54 136 }
mbed_official 30:91c1d09ada54 137 error("Couldn't setup requested SPI frequency");
mbed_official 30:91c1d09ada54 138 }
mbed_official 30:91c1d09ada54 139
mbed_official 30:91c1d09ada54 140 static inline int ssp_disable(spi_t *obj) {
mbed_official 30:91c1d09ada54 141 return obj->spi->CR1 &= ~(1 << 1);
mbed_official 30:91c1d09ada54 142 }
mbed_official 30:91c1d09ada54 143
mbed_official 30:91c1d09ada54 144 static inline int ssp_enable(spi_t *obj) {
mbed_official 30:91c1d09ada54 145 return obj->spi->CR1 |= (1 << 1);
mbed_official 30:91c1d09ada54 146 }
mbed_official 30:91c1d09ada54 147
mbed_official 30:91c1d09ada54 148 static inline int ssp_readable(spi_t *obj) {
mbed_official 30:91c1d09ada54 149 return obj->spi->SR & (1 << 2);
mbed_official 30:91c1d09ada54 150 }
mbed_official 30:91c1d09ada54 151
mbed_official 30:91c1d09ada54 152 static inline int ssp_writeable(spi_t *obj) {
mbed_official 30:91c1d09ada54 153 return obj->spi->SR & (1 << 1);
mbed_official 30:91c1d09ada54 154 }
mbed_official 30:91c1d09ada54 155
mbed_official 30:91c1d09ada54 156 static inline void ssp_write(spi_t *obj, int value) {
mbed_official 30:91c1d09ada54 157 while (!ssp_writeable(obj));
mbed_official 30:91c1d09ada54 158 obj->spi->DR = value;
mbed_official 30:91c1d09ada54 159 }
mbed_official 30:91c1d09ada54 160
mbed_official 30:91c1d09ada54 161 static inline int ssp_read(spi_t *obj) {
mbed_official 30:91c1d09ada54 162 while (!ssp_readable(obj));
mbed_official 30:91c1d09ada54 163 return obj->spi->DR;
mbed_official 30:91c1d09ada54 164 }
mbed_official 30:91c1d09ada54 165
mbed_official 30:91c1d09ada54 166 static inline int ssp_busy(spi_t *obj) {
mbed_official 30:91c1d09ada54 167 return (obj->spi->SR & (1 << 4)) ? (1) : (0);
mbed_official 30:91c1d09ada54 168 }
mbed_official 30:91c1d09ada54 169
mbed_official 30:91c1d09ada54 170 int spi_master_write(spi_t *obj, int value) {
mbed_official 30:91c1d09ada54 171 ssp_write(obj, value);
mbed_official 30:91c1d09ada54 172 return ssp_read(obj);
mbed_official 30:91c1d09ada54 173 }
mbed_official 30:91c1d09ada54 174
mbed_official 30:91c1d09ada54 175 int spi_slave_receive(spi_t *obj) {
mbed_official 30:91c1d09ada54 176 return (ssp_readable(obj) && !ssp_busy(obj)) ? (1) : (0);
mbed_official 30:91c1d09ada54 177 };
mbed_official 30:91c1d09ada54 178
mbed_official 30:91c1d09ada54 179 int spi_slave_read(spi_t *obj) {
mbed_official 30:91c1d09ada54 180 return obj->spi->DR;
mbed_official 30:91c1d09ada54 181 }
mbed_official 30:91c1d09ada54 182
mbed_official 30:91c1d09ada54 183 void spi_slave_write(spi_t *obj, int value) {
mbed_official 30:91c1d09ada54 184 while (ssp_writeable(obj) == 0) ;
mbed_official 30:91c1d09ada54 185 obj->spi->DR = value;
mbed_official 30:91c1d09ada54 186 }
mbed_official 30:91c1d09ada54 187
mbed_official 30:91c1d09ada54 188 int spi_busy(spi_t *obj) {
mbed_official 30:91c1d09ada54 189 return ssp_busy(obj);
mbed_official 30:91c1d09ada54 190 }