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Superseded

This library was superseded by mbed-dev - https://os.mbed.com/users/mbed_official/code/mbed-dev/.

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.

If you are looking for a stable and tested release, please import one of the official mbed library releases:

Import librarymbed

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_Freescale/TARGET_KLXX/TARGET_KL25Z/spi_api.c@111:ae4891ca7084, 2014-03-06 (annotated)

Committer:
mbed_official
Date:
Thu Mar 06 10:00:06 2014 +0000
Revision:
111:ae4891ca7084
Parent:
82:0b31dbcd4769
Child:
227:7bd0639b8911
Synchronized with git revision 955bd9a5c9e042f1cf30bbae2a99afaab8eb4cbf



Full URL: https://github.com/mbedmicro/mbed/commit/955bd9a5c9e042f1cf30bbae2a99afaab8eb4cbf/

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 82:0b31dbcd4769 1 /* mbed Microcontroller Library
mbed_official 82:0b31dbcd4769 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 82:0b31dbcd4769 3 *
mbed_official 82:0b31dbcd4769 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 82:0b31dbcd4769 5 * you may not use this file except in compliance with the License.
mbed_official 82:0b31dbcd4769 6 * You may obtain a copy of the License at
mbed_official 82:0b31dbcd4769 7 *
mbed_official 82:0b31dbcd4769 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 82:0b31dbcd4769 9 *
mbed_official 82:0b31dbcd4769 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 82:0b31dbcd4769 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 82:0b31dbcd4769 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 82:0b31dbcd4769 13 * See the License for the specific language governing permissions and
mbed_official 82:0b31dbcd4769 14 * limitations under the License.
mbed_official 82:0b31dbcd4769 15 */
mbed_official 82:0b31dbcd4769 16 #include "spi_api.h"
mbed_official 82:0b31dbcd4769 17
mbed_official 82:0b31dbcd4769 18 #include <math.h>
mbed_official 82:0b31dbcd4769 19
mbed_official 82:0b31dbcd4769 20 #include "cmsis.h"
mbed_official 82:0b31dbcd4769 21 #include "pinmap.h"
mbed_official 82:0b31dbcd4769 22 #include "error.h"
mbed_official 82:0b31dbcd4769 23 #include "clk_freqs.h"
mbed_official 82:0b31dbcd4769 24 #include "PeripheralPins.h"
mbed_official 82:0b31dbcd4769 25
mbed_official 82:0b31dbcd4769 26 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
mbed_official 82:0b31dbcd4769 27 // determine the SPI to use
mbed_official 82:0b31dbcd4769 28 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
mbed_official 82:0b31dbcd4769 29 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
mbed_official 82:0b31dbcd4769 30 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
mbed_official 82:0b31dbcd4769 31 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
mbed_official 82:0b31dbcd4769 32 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
mbed_official 82:0b31dbcd4769 33 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
mbed_official 82:0b31dbcd4769 34
mbed_official 82:0b31dbcd4769 35 obj->spi = (SPI_Type*)pinmap_merge(spi_data, spi_cntl);
mbed_official 82:0b31dbcd4769 36 if ((int)obj->spi == NC) {
mbed_official 82:0b31dbcd4769 37 error("SPI pinout mapping failed");
mbed_official 82:0b31dbcd4769 38 }
mbed_official 82:0b31dbcd4769 39
mbed_official 82:0b31dbcd4769 40 // enable power and clocking
mbed_official 82:0b31dbcd4769 41 switch ((int)obj->spi) {
mbed_official 82:0b31dbcd4769 42 case SPI_0: SIM->SCGC5 |= 1 << 11; SIM->SCGC4 |= 1 << 22; break;
mbed_official 82:0b31dbcd4769 43 case SPI_1: SIM->SCGC5 |= 1 << 13; SIM->SCGC4 |= 1 << 23; break;
mbed_official 82:0b31dbcd4769 44 }
mbed_official 82:0b31dbcd4769 45
mbed_official 82:0b31dbcd4769 46 // set default format and frequency
mbed_official 82:0b31dbcd4769 47 if (ssel == NC) {
mbed_official 82:0b31dbcd4769 48 spi_format(obj, 8, 0, 0); // 8 bits, mode 0, master
mbed_official 82:0b31dbcd4769 49 } else {
mbed_official 82:0b31dbcd4769 50 spi_format(obj, 8, 0, 1); // 8 bits, mode 0, slave
mbed_official 82:0b31dbcd4769 51 }
mbed_official 82:0b31dbcd4769 52 spi_frequency(obj, 1000000);
mbed_official 82:0b31dbcd4769 53
mbed_official 82:0b31dbcd4769 54 // enable SPI
mbed_official 82:0b31dbcd4769 55 obj->spi->C1 |= SPI_C1_SPE_MASK;
mbed_official 82:0b31dbcd4769 56
mbed_official 82:0b31dbcd4769 57 // pin out the spi pins
mbed_official 82:0b31dbcd4769 58 pinmap_pinout(mosi, PinMap_SPI_MOSI);
mbed_official 82:0b31dbcd4769 59 pinmap_pinout(miso, PinMap_SPI_MISO);
mbed_official 82:0b31dbcd4769 60 pinmap_pinout(sclk, PinMap_SPI_SCLK);
mbed_official 82:0b31dbcd4769 61 if (ssel != NC) {
mbed_official 82:0b31dbcd4769 62 pinmap_pinout(ssel, PinMap_SPI_SSEL);
mbed_official 82:0b31dbcd4769 63 }
mbed_official 82:0b31dbcd4769 64 }
mbed_official 82:0b31dbcd4769 65
mbed_official 82:0b31dbcd4769 66 void spi_free(spi_t *obj) {
mbed_official 82:0b31dbcd4769 67 // [TODO]
mbed_official 82:0b31dbcd4769 68 }
mbed_official 82:0b31dbcd4769 69 void spi_format(spi_t *obj, int bits, int mode, int slave) {
mbed_official 82:0b31dbcd4769 70 if (bits != 8) {
mbed_official 82:0b31dbcd4769 71 error("Only 8bits SPI supported");
mbed_official 82:0b31dbcd4769 72 }
mbed_official 82:0b31dbcd4769 73
mbed_official 82:0b31dbcd4769 74 if ((mode < 0) || (mode > 3)) {
mbed_official 82:0b31dbcd4769 75 error("SPI mode unsupported");
mbed_official 82:0b31dbcd4769 76 }
mbed_official 82:0b31dbcd4769 77
mbed_official 82:0b31dbcd4769 78 uint8_t polarity = (mode & 0x2) ? 1 : 0;
mbed_official 82:0b31dbcd4769 79 uint8_t phase = (mode & 0x1) ? 1 : 0;
mbed_official 82:0b31dbcd4769 80 uint8_t c1_data = ((!slave) << 4) | (polarity << 3) | (phase << 2);
mbed_official 82:0b31dbcd4769 81
mbed_official 82:0b31dbcd4769 82 // clear MSTR, CPOL and CPHA bits
mbed_official 82:0b31dbcd4769 83 obj->spi->C1 &= ~(0x7 << 2);
mbed_official 82:0b31dbcd4769 84
mbed_official 82:0b31dbcd4769 85 // write new value
mbed_official 82:0b31dbcd4769 86 obj->spi->C1 |= c1_data;
mbed_official 82:0b31dbcd4769 87 }
mbed_official 82:0b31dbcd4769 88
mbed_official 82:0b31dbcd4769 89 void spi_frequency(spi_t *obj, int hz) {
mbed_official 82:0b31dbcd4769 90 uint32_t error = 0;
mbed_official 82:0b31dbcd4769 91 uint32_t p_error = 0xffffffff;
mbed_official 82:0b31dbcd4769 92 uint32_t ref = 0;
mbed_official 82:0b31dbcd4769 93 uint8_t spr = 0;
mbed_official 82:0b31dbcd4769 94 uint8_t ref_spr = 0;
mbed_official 82:0b31dbcd4769 95 uint8_t ref_prescaler = 0;
mbed_official 82:0b31dbcd4769 96
mbed_official 82:0b31dbcd4769 97 // bus clk
mbed_official 82:0b31dbcd4769 98 uint32_t PCLK = bus_frequency();
mbed_official 82:0b31dbcd4769 99 uint8_t prescaler = 1;
mbed_official 82:0b31dbcd4769 100 uint8_t divisor = 2;
mbed_official 82:0b31dbcd4769 101
mbed_official 82:0b31dbcd4769 102 for (prescaler = 1; prescaler <= 8; prescaler++) {
mbed_official 82:0b31dbcd4769 103 divisor = 2;
mbed_official 82:0b31dbcd4769 104 for (spr = 0; spr <= 8; spr++, divisor *= 2) {
mbed_official 82:0b31dbcd4769 105 ref = PCLK / (prescaler*divisor);
mbed_official 82:0b31dbcd4769 106 if (ref > (uint32_t)hz)
mbed_official 82:0b31dbcd4769 107 continue;
mbed_official 82:0b31dbcd4769 108 error = hz - ref;
mbed_official 82:0b31dbcd4769 109 if (error < p_error) {
mbed_official 82:0b31dbcd4769 110 ref_spr = spr;
mbed_official 82:0b31dbcd4769 111 ref_prescaler = prescaler - 1;
mbed_official 82:0b31dbcd4769 112 p_error = error;
mbed_official 82:0b31dbcd4769 113 }
mbed_official 82:0b31dbcd4769 114 }
mbed_official 82:0b31dbcd4769 115 }
mbed_official 82:0b31dbcd4769 116
mbed_official 82:0b31dbcd4769 117 // set SPPR and SPR
mbed_official 82:0b31dbcd4769 118 obj->spi->BR = ((ref_prescaler & 0x7) << 4) | (ref_spr & 0xf);
mbed_official 82:0b31dbcd4769 119 }
mbed_official 82:0b31dbcd4769 120
mbed_official 82:0b31dbcd4769 121 static inline int spi_writeable(spi_t * obj) {
mbed_official 82:0b31dbcd4769 122 return (obj->spi->S & SPI_S_SPTEF_MASK) ? 1 : 0;
mbed_official 82:0b31dbcd4769 123 }
mbed_official 82:0b31dbcd4769 124
mbed_official 82:0b31dbcd4769 125 static inline int spi_readable(spi_t * obj) {
mbed_official 82:0b31dbcd4769 126 return (obj->spi->S & SPI_S_SPRF_MASK) ? 1 : 0;
mbed_official 82:0b31dbcd4769 127 }
mbed_official 82:0b31dbcd4769 128
mbed_official 82:0b31dbcd4769 129 int spi_master_write(spi_t *obj, int value) {
mbed_official 82:0b31dbcd4769 130 // wait tx buffer empty
mbed_official 82:0b31dbcd4769 131 while(!spi_writeable(obj));
mbed_official 82:0b31dbcd4769 132 obj->spi->D = (value & 0xff);
mbed_official 82:0b31dbcd4769 133
mbed_official 82:0b31dbcd4769 134 // wait rx buffer full
mbed_official 82:0b31dbcd4769 135 while (!spi_readable(obj));
mbed_official 82:0b31dbcd4769 136 return obj->spi->D & 0xff;
mbed_official 82:0b31dbcd4769 137 }
mbed_official 82:0b31dbcd4769 138
mbed_official 82:0b31dbcd4769 139 int spi_slave_receive(spi_t *obj) {
mbed_official 82:0b31dbcd4769 140 return spi_readable(obj);
mbed_official 82:0b31dbcd4769 141 }
mbed_official 82:0b31dbcd4769 142
mbed_official 82:0b31dbcd4769 143 int spi_slave_read(spi_t *obj) {
mbed_official 82:0b31dbcd4769 144 return obj->spi->D;
mbed_official 82:0b31dbcd4769 145 }
mbed_official 82:0b31dbcd4769 146
mbed_official 82:0b31dbcd4769 147 void spi_slave_write(spi_t *obj, int value) {
mbed_official 82:0b31dbcd4769 148 while (!spi_writeable(obj));
mbed_official 82:0b31dbcd4769 149 obj->spi->D = value;
mbed_official 82:0b31dbcd4769 150 }