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Fork of OmniWheels by Gustav Atmel

mbed-os/targets/TARGET_NXP/TARGET_LPC11U6X/spi_api.c@1:9c5af431a1f1, 2018-05-01 (annotated)

Committer:
gustavatmel
Date:
Tue May 01 15:47:08 2018 +0000
Revision:
1:9c5af431a1f1
sdf

Who changed what in which revision?

UserRevisionLine numberNew contents of line
gustavatmel 1:9c5af431a1f1 1 /* mbed Microcontroller Library
gustavatmel 1:9c5af431a1f1 2 * Copyright (c) 2006-2013 ARM Limited
gustavatmel 1:9c5af431a1f1 3 *
gustavatmel 1:9c5af431a1f1 4 * Licensed under the Apache License, Version 2.0 (the "License");
gustavatmel 1:9c5af431a1f1 5 * you may not use this file except in compliance with the License.
gustavatmel 1:9c5af431a1f1 6 * You may obtain a copy of the License at
gustavatmel 1:9c5af431a1f1 7 *
gustavatmel 1:9c5af431a1f1 8 * http://www.apache.org/licenses/LICENSE-2.0
gustavatmel 1:9c5af431a1f1 9 *
gustavatmel 1:9c5af431a1f1 10 * Unless required by applicable law or agreed to in writing, software
gustavatmel 1:9c5af431a1f1 11 * distributed under the License is distributed on an "AS IS" BASIS,
gustavatmel 1:9c5af431a1f1 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
gustavatmel 1:9c5af431a1f1 13 * See the License for the specific language governing permissions and
gustavatmel 1:9c5af431a1f1 14 * limitations under the License.
gustavatmel 1:9c5af431a1f1 15 */
gustavatmel 1:9c5af431a1f1 16 #include "mbed_assert.h"
gustavatmel 1:9c5af431a1f1 17 #include <math.h>
gustavatmel 1:9c5af431a1f1 18
gustavatmel 1:9c5af431a1f1 19 #include "spi_api.h"
gustavatmel 1:9c5af431a1f1 20 #include "cmsis.h"
gustavatmel 1:9c5af431a1f1 21 #include "pinmap.h"
gustavatmel 1:9c5af431a1f1 22 #include "mbed_error.h"
gustavatmel 1:9c5af431a1f1 23
gustavatmel 1:9c5af431a1f1 24 #if DEVICE_SPI
gustavatmel 1:9c5af431a1f1 25
gustavatmel 1:9c5af431a1f1 26 static const PinMap PinMap_SPI_SCLK[] = {
gustavatmel 1:9c5af431a1f1 27 {P0_6 , SPI_0, 0x02},
gustavatmel 1:9c5af431a1f1 28 {P1_29, SPI_0, 0x01},
gustavatmel 1:9c5af431a1f1 29 {P2_7 , SPI_0, 0x01},
gustavatmel 1:9c5af431a1f1 30 {P1_20, SPI_1, 0x02},
gustavatmel 1:9c5af431a1f1 31 {P1_27, SPI_1, 0x04},
gustavatmel 1:9c5af431a1f1 32 {NC , NC , 0}
gustavatmel 1:9c5af431a1f1 33 };
gustavatmel 1:9c5af431a1f1 34
gustavatmel 1:9c5af431a1f1 35 static const PinMap PinMap_SPI_MOSI[] = {
gustavatmel 1:9c5af431a1f1 36 {P0_9 , SPI_0, 0x01},
gustavatmel 1:9c5af431a1f1 37 {P1_12, SPI_0, 0x01},
gustavatmel 1:9c5af431a1f1 38 {P0_21, SPI_1, 0x02},
gustavatmel 1:9c5af431a1f1 39 {P1_22, SPI_1, 0x01},
gustavatmel 1:9c5af431a1f1 40 {NC , NC , 0}
gustavatmel 1:9c5af431a1f1 41 };
gustavatmel 1:9c5af431a1f1 42
gustavatmel 1:9c5af431a1f1 43 static const PinMap PinMap_SPI_MISO[] = {
gustavatmel 1:9c5af431a1f1 44 {P0_8 , SPI_0, 0x01},
gustavatmel 1:9c5af431a1f1 45 {P1_16, SPI_0, 0x01},
gustavatmel 1:9c5af431a1f1 46 {P0_22, SPI_1, 0x03},
gustavatmel 1:9c5af431a1f1 47 {P1_21, SPI_1, 0x02},
gustavatmel 1:9c5af431a1f1 48 {NC , NC , 0}
gustavatmel 1:9c5af431a1f1 49 };
gustavatmel 1:9c5af431a1f1 50
gustavatmel 1:9c5af431a1f1 51 static const PinMap PinMap_SPI_SSEL[] = {
gustavatmel 1:9c5af431a1f1 52 {P0_2 , SPI_0, 0x01},
gustavatmel 1:9c5af431a1f1 53 {P1_15, SPI_0, 0x01},
gustavatmel 1:9c5af431a1f1 54 {P0_23, SPI_1, 0x04},
gustavatmel 1:9c5af431a1f1 55 {P1_23, SPI_1, 0x02},
gustavatmel 1:9c5af431a1f1 56 {NC , NC , 0}
gustavatmel 1:9c5af431a1f1 57 };
gustavatmel 1:9c5af431a1f1 58
gustavatmel 1:9c5af431a1f1 59 static inline int ssp_disable(spi_t *obj);
gustavatmel 1:9c5af431a1f1 60 static inline int ssp_enable(spi_t *obj);
gustavatmel 1:9c5af431a1f1 61
gustavatmel 1:9c5af431a1f1 62 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
gustavatmel 1:9c5af431a1f1 63 // determine the SPI to use
gustavatmel 1:9c5af431a1f1 64 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
gustavatmel 1:9c5af431a1f1 65 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
gustavatmel 1:9c5af431a1f1 66 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
gustavatmel 1:9c5af431a1f1 67 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
gustavatmel 1:9c5af431a1f1 68 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
gustavatmel 1:9c5af431a1f1 69 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
gustavatmel 1:9c5af431a1f1 70
gustavatmel 1:9c5af431a1f1 71 obj->spi = (LPC_SSP0_Type*)pinmap_merge(spi_data, spi_cntl);
gustavatmel 1:9c5af431a1f1 72 MBED_ASSERT((int)obj->spi != NC);
gustavatmel 1:9c5af431a1f1 73
gustavatmel 1:9c5af431a1f1 74 // enable power and clocking
gustavatmel 1:9c5af431a1f1 75 switch ((int)obj->spi) {
gustavatmel 1:9c5af431a1f1 76 case SPI_0:
gustavatmel 1:9c5af431a1f1 77 LPC_SYSCON->SYSAHBCLKCTRL |= 1 << 11;
gustavatmel 1:9c5af431a1f1 78 LPC_SYSCON->SSP0CLKDIV = 0x01;
gustavatmel 1:9c5af431a1f1 79 LPC_SYSCON->PRESETCTRL |= 1 << 0;
gustavatmel 1:9c5af431a1f1 80 break;
gustavatmel 1:9c5af431a1f1 81 case SPI_1:
gustavatmel 1:9c5af431a1f1 82 LPC_SYSCON->SYSAHBCLKCTRL |= 1 << 18;
gustavatmel 1:9c5af431a1f1 83 LPC_SYSCON->SSP1CLKDIV = 0x01;
gustavatmel 1:9c5af431a1f1 84 LPC_SYSCON->PRESETCTRL |= 1 << 2;
gustavatmel 1:9c5af431a1f1 85 break;
gustavatmel 1:9c5af431a1f1 86 }
gustavatmel 1:9c5af431a1f1 87
gustavatmel 1:9c5af431a1f1 88 // pin out the spi pins
gustavatmel 1:9c5af431a1f1 89 pinmap_pinout(mosi, PinMap_SPI_MOSI);
gustavatmel 1:9c5af431a1f1 90 pinmap_pinout(miso, PinMap_SPI_MISO);
gustavatmel 1:9c5af431a1f1 91 pinmap_pinout(sclk, PinMap_SPI_SCLK);
gustavatmel 1:9c5af431a1f1 92 if (ssel != NC) {
gustavatmel 1:9c5af431a1f1 93 pinmap_pinout(ssel, PinMap_SPI_SSEL);
gustavatmel 1:9c5af431a1f1 94 }
gustavatmel 1:9c5af431a1f1 95 }
gustavatmel 1:9c5af431a1f1 96
gustavatmel 1:9c5af431a1f1 97 void spi_free(spi_t *obj) {}
gustavatmel 1:9c5af431a1f1 98
gustavatmel 1:9c5af431a1f1 99 void spi_format(spi_t *obj, int bits, int mode, int slave) {
gustavatmel 1:9c5af431a1f1 100 ssp_disable(obj);
gustavatmel 1:9c5af431a1f1 101 MBED_ASSERT(((bits >= 4) && (bits <= 16)) || ((mode >= 0) && (mode <= 3)));
gustavatmel 1:9c5af431a1f1 102
gustavatmel 1:9c5af431a1f1 103 int polarity = (mode & 0x2) ? 1 : 0;
gustavatmel 1:9c5af431a1f1 104 int phase = (mode & 0x1) ? 1 : 0;
gustavatmel 1:9c5af431a1f1 105
gustavatmel 1:9c5af431a1f1 106 // set it up
gustavatmel 1:9c5af431a1f1 107 int DSS = bits - 1; // DSS (data select size)
gustavatmel 1:9c5af431a1f1 108 int SPO = (polarity) ? 1 : 0; // SPO - clock out polarity
gustavatmel 1:9c5af431a1f1 109 int SPH = (phase) ? 1 : 0; // SPH - clock out phase
gustavatmel 1:9c5af431a1f1 110
gustavatmel 1:9c5af431a1f1 111 int FRF = 0; // FRF (frame format) = SPI
gustavatmel 1:9c5af431a1f1 112 uint32_t tmp = obj->spi->CR0;
gustavatmel 1:9c5af431a1f1 113 tmp &= ~(0x00FF); // Clear DSS, FRF, CPOL and CPHA [7:0]
gustavatmel 1:9c5af431a1f1 114 tmp |= DSS << 0
gustavatmel 1:9c5af431a1f1 115 | FRF << 4
gustavatmel 1:9c5af431a1f1 116 | SPO << 6
gustavatmel 1:9c5af431a1f1 117 | SPH << 7;
gustavatmel 1:9c5af431a1f1 118 obj->spi->CR0 = tmp;
gustavatmel 1:9c5af431a1f1 119
gustavatmel 1:9c5af431a1f1 120 tmp = obj->spi->CR1;
gustavatmel 1:9c5af431a1f1 121 tmp &= ~(0xD);
gustavatmel 1:9c5af431a1f1 122 tmp |= 0 << 0 // LBM - loop back mode - off
gustavatmel 1:9c5af431a1f1 123 | ((slave) ? 1 : 0) << 2 // MS - master slave mode, 1 = slave
gustavatmel 1:9c5af431a1f1 124 | 0 << 3; // SOD - slave output disable - na
gustavatmel 1:9c5af431a1f1 125 obj->spi->CR1 = tmp;
gustavatmel 1:9c5af431a1f1 126
gustavatmel 1:9c5af431a1f1 127 ssp_enable(obj);
gustavatmel 1:9c5af431a1f1 128 }
gustavatmel 1:9c5af431a1f1 129
gustavatmel 1:9c5af431a1f1 130 void spi_frequency(spi_t *obj, int hz) {
gustavatmel 1:9c5af431a1f1 131 ssp_disable(obj);
gustavatmel 1:9c5af431a1f1 132
gustavatmel 1:9c5af431a1f1 133 uint32_t PCLK = SystemCoreClock;
gustavatmel 1:9c5af431a1f1 134
gustavatmel 1:9c5af431a1f1 135 int prescaler;
gustavatmel 1:9c5af431a1f1 136
gustavatmel 1:9c5af431a1f1 137 for (prescaler = 2; prescaler <= 254; prescaler += 2) {
gustavatmel 1:9c5af431a1f1 138 int prescale_hz = PCLK / prescaler;
gustavatmel 1:9c5af431a1f1 139
gustavatmel 1:9c5af431a1f1 140 // calculate the divider
gustavatmel 1:9c5af431a1f1 141 int divider = floor(((float)prescale_hz / (float)hz) + 0.5f);
gustavatmel 1:9c5af431a1f1 142
gustavatmel 1:9c5af431a1f1 143 // check we can support the divider
gustavatmel 1:9c5af431a1f1 144 if (divider < 256) {
gustavatmel 1:9c5af431a1f1 145 // prescaler
gustavatmel 1:9c5af431a1f1 146 obj->spi->CPSR = prescaler;
gustavatmel 1:9c5af431a1f1 147
gustavatmel 1:9c5af431a1f1 148 // divider
gustavatmel 1:9c5af431a1f1 149 obj->spi->CR0 &= ~(0xFF00); // Clear SCR: Serial clock rate [15:8]
gustavatmel 1:9c5af431a1f1 150 obj->spi->CR0 |= (divider - 1) << 8;
gustavatmel 1:9c5af431a1f1 151 ssp_enable(obj);
gustavatmel 1:9c5af431a1f1 152 return;
gustavatmel 1:9c5af431a1f1 153 }
gustavatmel 1:9c5af431a1f1 154 }
gustavatmel 1:9c5af431a1f1 155 error("Couldn't setup requested SPI frequency");
gustavatmel 1:9c5af431a1f1 156 }
gustavatmel 1:9c5af431a1f1 157
gustavatmel 1:9c5af431a1f1 158 static inline int ssp_disable(spi_t *obj) {
gustavatmel 1:9c5af431a1f1 159 return obj->spi->CR1 &= ~(1 << 1);
gustavatmel 1:9c5af431a1f1 160 }
gustavatmel 1:9c5af431a1f1 161
gustavatmel 1:9c5af431a1f1 162 static inline int ssp_enable(spi_t *obj) {
gustavatmel 1:9c5af431a1f1 163 return obj->spi->CR1 |= (1 << 1);
gustavatmel 1:9c5af431a1f1 164 }
gustavatmel 1:9c5af431a1f1 165
gustavatmel 1:9c5af431a1f1 166 static inline int ssp_readable(spi_t *obj) {
gustavatmel 1:9c5af431a1f1 167 return obj->spi->SR & (1 << 2);
gustavatmel 1:9c5af431a1f1 168 }
gustavatmel 1:9c5af431a1f1 169
gustavatmel 1:9c5af431a1f1 170 static inline int ssp_writeable(spi_t *obj) {
gustavatmel 1:9c5af431a1f1 171 return obj->spi->SR & (1 << 1);
gustavatmel 1:9c5af431a1f1 172 }
gustavatmel 1:9c5af431a1f1 173
gustavatmel 1:9c5af431a1f1 174 static inline void ssp_write(spi_t *obj, int value) {
gustavatmel 1:9c5af431a1f1 175 while (!ssp_writeable(obj));
gustavatmel 1:9c5af431a1f1 176 obj->spi->DR = value;
gustavatmel 1:9c5af431a1f1 177 }
gustavatmel 1:9c5af431a1f1 178
gustavatmel 1:9c5af431a1f1 179 static inline int ssp_read(spi_t *obj) {
gustavatmel 1:9c5af431a1f1 180 while (!ssp_readable(obj));
gustavatmel 1:9c5af431a1f1 181 return obj->spi->DR;
gustavatmel 1:9c5af431a1f1 182 }
gustavatmel 1:9c5af431a1f1 183
gustavatmel 1:9c5af431a1f1 184 static inline int ssp_busy(spi_t *obj) {
gustavatmel 1:9c5af431a1f1 185 return (obj->spi->SR & (1 << 4)) ? (1) : (0);
gustavatmel 1:9c5af431a1f1 186 }
gustavatmel 1:9c5af431a1f1 187
gustavatmel 1:9c5af431a1f1 188 int spi_master_write(spi_t *obj, int value) {
gustavatmel 1:9c5af431a1f1 189 ssp_write(obj, value);
gustavatmel 1:9c5af431a1f1 190 return ssp_read(obj);
gustavatmel 1:9c5af431a1f1 191 }
gustavatmel 1:9c5af431a1f1 192
gustavatmel 1:9c5af431a1f1 193 int spi_master_block_write(spi_t *obj, const char *tx_buffer, int tx_length,
gustavatmel 1:9c5af431a1f1 194 char *rx_buffer, int rx_length, char write_fill) {
gustavatmel 1:9c5af431a1f1 195 int total = (tx_length > rx_length) ? tx_length : rx_length;
gustavatmel 1:9c5af431a1f1 196
gustavatmel 1:9c5af431a1f1 197 for (int i = 0; i < total; i++) {
gustavatmel 1:9c5af431a1f1 198 char out = (i < tx_length) ? tx_buffer[i] : write_fill;
gustavatmel 1:9c5af431a1f1 199 char in = spi_master_write(obj, out);
gustavatmel 1:9c5af431a1f1 200 if (i < rx_length) {
gustavatmel 1:9c5af431a1f1 201 rx_buffer[i] = in;
gustavatmel 1:9c5af431a1f1 202 }
gustavatmel 1:9c5af431a1f1 203 }
gustavatmel 1:9c5af431a1f1 204
gustavatmel 1:9c5af431a1f1 205 return total;
gustavatmel 1:9c5af431a1f1 206 }
gustavatmel 1:9c5af431a1f1 207
gustavatmel 1:9c5af431a1f1 208 int spi_slave_receive(spi_t *obj) {
gustavatmel 1:9c5af431a1f1 209 return (ssp_readable(obj) && !ssp_busy(obj)) ? (1) : (0);
gustavatmel 1:9c5af431a1f1 210 }
gustavatmel 1:9c5af431a1f1 211
gustavatmel 1:9c5af431a1f1 212 int spi_slave_read(spi_t *obj) {
gustavatmel 1:9c5af431a1f1 213 return obj->spi->DR;
gustavatmel 1:9c5af431a1f1 214 }
gustavatmel 1:9c5af431a1f1 215
gustavatmel 1:9c5af431a1f1 216 void spi_slave_write(spi_t *obj, int value) {
gustavatmel 1:9c5af431a1f1 217 while (ssp_writeable(obj) == 0) ;
gustavatmel 1:9c5af431a1f1 218 obj->spi->DR = value;
gustavatmel 1:9c5af431a1f1 219 }
gustavatmel 1:9c5af431a1f1 220
gustavatmel 1:9c5af431a1f1 221 int spi_busy(spi_t *obj) {
gustavatmel 1:9c5af431a1f1 222 return ssp_busy(obj);
gustavatmel 1:9c5af431a1f1 223 }
gustavatmel 1:9c5af431a1f1 224
gustavatmel 1:9c5af431a1f1 225 #endif