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targets/hal/TARGET_Freescale/TARGET_K20D5M/spi_api.c@68:41613245dfd7, 2013-12-26 (annotated)

Committer:
mbed_official
Date:
Thu Dec 26 13:00:06 2013 +0000
Revision:
68:41613245dfd7
Child:
73:299c67215126
Synchronized with git revision fba199a9c4445231b0f38e1e113c118182635546



Full URL: https://github.com/mbedmicro/mbed/commit/fba199a9c4445231b0f38e1e113c118182635546/



target K20D5M

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 68:41613245dfd7 1 /* mbed Microcontroller Library
mbed_official 68:41613245dfd7 2 * Copyright (c) 2013 ARM Limited
mbed_official 68:41613245dfd7 3 *
mbed_official 68:41613245dfd7 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 68:41613245dfd7 5 * you may not use this file except in compliance with the License.
mbed_official 68:41613245dfd7 6 * You may obtain a copy of the License at
mbed_official 68:41613245dfd7 7 *
mbed_official 68:41613245dfd7 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 68:41613245dfd7 9 *
mbed_official 68:41613245dfd7 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 68:41613245dfd7 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 68:41613245dfd7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 68:41613245dfd7 13 * See the License for the specific language governing permissions and
mbed_official 68:41613245dfd7 14 * limitations under the License.
mbed_official 68:41613245dfd7 15 */
mbed_official 68:41613245dfd7 16 #include "spi_api.h"
mbed_official 68:41613245dfd7 17
mbed_official 68:41613245dfd7 18 #include <math.h>
mbed_official 68:41613245dfd7 19
mbed_official 68:41613245dfd7 20 #include "cmsis.h"
mbed_official 68:41613245dfd7 21 #include "pinmap.h"
mbed_official 68:41613245dfd7 22 #include "error.h"
mbed_official 68:41613245dfd7 23
mbed_official 68:41613245dfd7 24 static const PinMap PinMap_SPI_SCLK[] = {
mbed_official 68:41613245dfd7 25 {PTC5, SPI_0, 2},
mbed_official 68:41613245dfd7 26 {PTD1, SPI_0, 2},
mbed_official 68:41613245dfd7 27 {NC , NC , 0}
mbed_official 68:41613245dfd7 28 };
mbed_official 68:41613245dfd7 29
mbed_official 68:41613245dfd7 30 static const PinMap PinMap_SPI_MOSI[] = {
mbed_official 68:41613245dfd7 31 {PTD2, SPI_0, 2},
mbed_official 68:41613245dfd7 32 {PTC6, SPI_0, 2},
mbed_official 68:41613245dfd7 33 {NC , NC , 0}
mbed_official 68:41613245dfd7 34 };
mbed_official 68:41613245dfd7 35
mbed_official 68:41613245dfd7 36 static const PinMap PinMap_SPI_MISO[] = {
mbed_official 68:41613245dfd7 37 {PTD3, SPI_0, 2},
mbed_official 68:41613245dfd7 38 {PTC7, SPI_0, 2},
mbed_official 68:41613245dfd7 39 {NC , NC , 0}
mbed_official 68:41613245dfd7 40 };
mbed_official 68:41613245dfd7 41
mbed_official 68:41613245dfd7 42 static const PinMap PinMap_SPI_SSEL[] = {
mbed_official 68:41613245dfd7 43 {PTD0, SPI_0, 2},
mbed_official 68:41613245dfd7 44 {PTC4, SPI_0, 2},
mbed_official 68:41613245dfd7 45 {NC , NC , 0}
mbed_official 68:41613245dfd7 46 };
mbed_official 68:41613245dfd7 47
mbed_official 68:41613245dfd7 48 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
mbed_official 68:41613245dfd7 49 // determine the SPI to use
mbed_official 68:41613245dfd7 50 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
mbed_official 68:41613245dfd7 51 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
mbed_official 68:41613245dfd7 52 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
mbed_official 68:41613245dfd7 53 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
mbed_official 68:41613245dfd7 54 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
mbed_official 68:41613245dfd7 55 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
mbed_official 68:41613245dfd7 56
mbed_official 68:41613245dfd7 57 obj->spi = (SPI_Type*)pinmap_merge(spi_data, spi_cntl);
mbed_official 68:41613245dfd7 58 if ((int)obj->spi == NC) {
mbed_official 68:41613245dfd7 59 error("SPI pinout mapping failed");
mbed_official 68:41613245dfd7 60 }
mbed_official 68:41613245dfd7 61
mbed_official 68:41613245dfd7 62 SIM->SCGC5 |= (1 << 11) | (1 << 12); // PortC & D
mbed_official 68:41613245dfd7 63 SIM->SCGC6 |= 1 << 12; // spi clocks
mbed_official 68:41613245dfd7 64
mbed_official 68:41613245dfd7 65 // halted state
mbed_official 68:41613245dfd7 66 obj->spi->MCR = SPI_MCR_HALT_MASK;
mbed_official 68:41613245dfd7 67
mbed_official 68:41613245dfd7 68 // set default format and frequency
mbed_official 68:41613245dfd7 69 if (ssel == NC) {
mbed_official 68:41613245dfd7 70 spi_format(obj, 8, 0, 0); // 8 bits, mode 0, master
mbed_official 68:41613245dfd7 71 } else {
mbed_official 68:41613245dfd7 72 spi_format(obj, 8, 0, 1); // 8 bits, mode 0, slave
mbed_official 68:41613245dfd7 73 }
mbed_official 68:41613245dfd7 74 spi_frequency(obj, 1000000);
mbed_official 68:41613245dfd7 75
mbed_official 68:41613245dfd7 76 // not halt in the debug mode
mbed_official 68:41613245dfd7 77 obj->spi->SR |= SPI_SR_EOQF_MASK;
mbed_official 68:41613245dfd7 78 // enable SPI
mbed_official 68:41613245dfd7 79 obj->spi->MCR &= (~SPI_MCR_HALT_MASK);
mbed_official 68:41613245dfd7 80
mbed_official 68:41613245dfd7 81 // pin out the spi pins
mbed_official 68:41613245dfd7 82 pinmap_pinout(mosi, PinMap_SPI_MOSI);
mbed_official 68:41613245dfd7 83 pinmap_pinout(miso, PinMap_SPI_MISO);
mbed_official 68:41613245dfd7 84 pinmap_pinout(sclk, PinMap_SPI_SCLK);
mbed_official 68:41613245dfd7 85 if (ssel != NC) {
mbed_official 68:41613245dfd7 86 pinmap_pinout(ssel, PinMap_SPI_SSEL);
mbed_official 68:41613245dfd7 87 }
mbed_official 68:41613245dfd7 88 }
mbed_official 68:41613245dfd7 89
mbed_official 68:41613245dfd7 90 void spi_free(spi_t *obj) {
mbed_official 68:41613245dfd7 91 // [TODO]
mbed_official 68:41613245dfd7 92 }
mbed_official 68:41613245dfd7 93 void spi_format(spi_t *obj, int bits, int mode, int slave) {
mbed_official 68:41613245dfd7 94 if ((bits != 8) && (bits != 16)) {
mbed_official 68:41613245dfd7 95 error("Only 8/16 bits SPI supported");
mbed_official 68:41613245dfd7 96 }
mbed_official 68:41613245dfd7 97
mbed_official 68:41613245dfd7 98 if ((mode < 0) || (mode > 3)) {
mbed_official 68:41613245dfd7 99 error("SPI mode unsupported");
mbed_official 68:41613245dfd7 100 }
mbed_official 68:41613245dfd7 101
mbed_official 68:41613245dfd7 102 uint32_t polarity = (mode & 0x2) ? 1 : 0;
mbed_official 68:41613245dfd7 103 uint32_t phase = (mode & 0x1) ? 1 : 0;
mbed_official 68:41613245dfd7 104
mbed_official 68:41613245dfd7 105 // set master/slave
mbed_official 68:41613245dfd7 106 obj->spi->MCR &= ~SPI_MCR_MSTR_MASK;
mbed_official 68:41613245dfd7 107 obj->spi->MCR |= ((!slave) << SPI_MCR_MSTR_SHIFT);
mbed_official 68:41613245dfd7 108
mbed_official 68:41613245dfd7 109 // CTAR0 is used
mbed_official 68:41613245dfd7 110 obj->spi->CTAR[0] &= ~(SPI_CTAR_CPHA_MASK | SPI_CTAR_CPOL_MASK);
mbed_official 68:41613245dfd7 111 obj->spi->CTAR[0] |= (polarity << SPI_CTAR_CPOL_SHIFT) | (phase << SPI_CTAR_CPHA_SHIFT);
mbed_official 68:41613245dfd7 112 }
mbed_official 68:41613245dfd7 113
mbed_official 68:41613245dfd7 114 void spi_frequency(spi_t *obj, int hz) {
mbed_official 68:41613245dfd7 115 uint32_t error = 0;
mbed_official 68:41613245dfd7 116 uint32_t p_error = 0xffffffff;
mbed_official 68:41613245dfd7 117 uint32_t ref = 0;
mbed_official 68:41613245dfd7 118 uint32_t spr = 0;
mbed_official 68:41613245dfd7 119 uint32_t ref_spr = 0;
mbed_official 68:41613245dfd7 120 uint32_t ref_prescaler = 0;
mbed_official 68:41613245dfd7 121
mbed_official 68:41613245dfd7 122 // bus clk
mbed_official 68:41613245dfd7 123 uint32_t PCLK = 48000000u;
mbed_official 68:41613245dfd7 124 uint32_t prescaler = 1;
mbed_official 68:41613245dfd7 125 uint32_t divisor = 2;
mbed_official 68:41613245dfd7 126
mbed_official 68:41613245dfd7 127 for (prescaler = 1; prescaler <= 8; prescaler++) {
mbed_official 68:41613245dfd7 128 divisor = 2;
mbed_official 68:41613245dfd7 129 for (spr = 0; spr <= 8; spr++, divisor *= 2) {
mbed_official 68:41613245dfd7 130 ref = PCLK / (prescaler*divisor);
mbed_official 68:41613245dfd7 131 if (ref > (uint32_t)hz)
mbed_official 68:41613245dfd7 132 continue;
mbed_official 68:41613245dfd7 133 error = hz - ref;
mbed_official 68:41613245dfd7 134 if (error < p_error) {
mbed_official 68:41613245dfd7 135 ref_spr = spr;
mbed_official 68:41613245dfd7 136 ref_prescaler = prescaler - 1;
mbed_official 68:41613245dfd7 137 p_error = error;
mbed_official 68:41613245dfd7 138 }
mbed_official 68:41613245dfd7 139 }
mbed_official 68:41613245dfd7 140 }
mbed_official 68:41613245dfd7 141
mbed_official 68:41613245dfd7 142 // set SPPR and SPR
mbed_official 68:41613245dfd7 143 obj->spi->CTAR[0] = ((ref_prescaler & 0x7) << 4) | (ref_spr & 0xf);
mbed_official 68:41613245dfd7 144 }
mbed_official 68:41613245dfd7 145
mbed_official 68:41613245dfd7 146 static inline int spi_writeable(spi_t * obj) {
mbed_official 68:41613245dfd7 147 return (obj->spi->SR & SPI_SR_TCF_MASK) ? 1 : 0;
mbed_official 68:41613245dfd7 148 }
mbed_official 68:41613245dfd7 149
mbed_official 68:41613245dfd7 150 static inline int spi_readable(spi_t * obj) {
mbed_official 68:41613245dfd7 151 return (obj->spi->SR & SPI_SR_TFFF_MASK) ? 1 : 0;
mbed_official 68:41613245dfd7 152 }
mbed_official 68:41613245dfd7 153
mbed_official 68:41613245dfd7 154 int spi_master_write(spi_t *obj, int value) {
mbed_official 68:41613245dfd7 155 // wait tx buffer empty
mbed_official 68:41613245dfd7 156 while(!spi_writeable(obj));
mbed_official 68:41613245dfd7 157 obj->spi->PUSHR = SPI_PUSHR_TXDATA(value & 0xff);
mbed_official 68:41613245dfd7 158
mbed_official 68:41613245dfd7 159 // wait rx buffer full
mbed_official 68:41613245dfd7 160 while (!spi_readable(obj));
mbed_official 68:41613245dfd7 161 return obj->spi->POPR;
mbed_official 68:41613245dfd7 162 }
mbed_official 68:41613245dfd7 163
mbed_official 68:41613245dfd7 164 int spi_slave_receive(spi_t *obj) {
mbed_official 68:41613245dfd7 165 return spi_readable(obj);
mbed_official 68:41613245dfd7 166 }
mbed_official 68:41613245dfd7 167
mbed_official 68:41613245dfd7 168 int spi_slave_read(spi_t *obj) {
mbed_official 68:41613245dfd7 169 return obj->spi->POPR;
mbed_official 68:41613245dfd7 170 }
mbed_official 68:41613245dfd7 171
mbed_official 68:41613245dfd7 172 void spi_slave_write(spi_t *obj, int value) {
mbed_official 68:41613245dfd7 173 while (!spi_writeable(obj));
mbed_official 68:41613245dfd7 174 }