marcus chiou / mbed-src

mbed library sources

Fork of mbed-src by mbed official

targets/hal/TARGET_Freescale/TARGET_K20XX/spi_api.c@620:49241b7c6da5, 2015-09-07 (annotated)

Committer:
mbed_official
Date:
Mon Sep 07 10:00:10 2015 +0100
Revision:
620:49241b7c6da5
Parent:
552:a1b9575155a3 
Synchronized with git revision 40a175b1680be9491456d7895baf5a7b7cabd1f9



Full URL: https://github.com/mbedmicro/mbed/commit/40a175b1680be9491456d7895baf5a7b7cabd1f9/



Fix a signed and unsigned integer comparison warning

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 445:3312ed629f01 1 /* mbed Microcontroller Library
mbed_official 445:3312ed629f01 2 * Copyright (c) 2015 ARM Limited
mbed_official 445:3312ed629f01 3 *
mbed_official 445:3312ed629f01 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 445:3312ed629f01 5 * you may not use this file except in compliance with the License.
mbed_official 445:3312ed629f01 6 * You may obtain a copy of the License at
mbed_official 445:3312ed629f01 7 *
mbed_official 445:3312ed629f01 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 445:3312ed629f01 9 *
mbed_official 445:3312ed629f01 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 445:3312ed629f01 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 445:3312ed629f01 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 445:3312ed629f01 13 * See the License for the specific language governing permissions and
mbed_official 445:3312ed629f01 14 * limitations under the License.
mbed_official 445:3312ed629f01 15 */
mbed_official 445:3312ed629f01 16 #include "mbed_assert.h"
mbed_official 445:3312ed629f01 17 #include "spi_api.h"
mbed_official 445:3312ed629f01 18
mbed_official 445:3312ed629f01 19 #include <math.h>
mbed_official 445:3312ed629f01 20
mbed_official 445:3312ed629f01 21 #include "cmsis.h"
mbed_official 445:3312ed629f01 22 #include "pinmap.h"
mbed_official 445:3312ed629f01 23 #include "clk_freqs.h"
mbed_official 445:3312ed629f01 24 #include "PeripheralPins.h"
mbed_official 445:3312ed629f01 25
mbed_official 445:3312ed629f01 26 void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
mbed_official 445:3312ed629f01 27 // determine the SPI to use
mbed_official 445:3312ed629f01 28 SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
mbed_official 445:3312ed629f01 29 SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
mbed_official 445:3312ed629f01 30 SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
mbed_official 445:3312ed629f01 31 SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
mbed_official 445:3312ed629f01 32 SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
mbed_official 445:3312ed629f01 33 SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
mbed_official 445:3312ed629f01 34
mbed_official 445:3312ed629f01 35 obj->spi = (SPI_Type*)pinmap_merge(spi_data, spi_cntl);
mbed_official 445:3312ed629f01 36 MBED_ASSERT((int)obj->spi != NC);
mbed_official 445:3312ed629f01 37
mbed_official 445:3312ed629f01 38 SIM->SCGC5 |= SIM_SCGC5_PORTC_MASK | SIM_SCGC5_PORTD_MASK;
mbed_official 445:3312ed629f01 39 SIM->SCGC6 |= SIM_SCGC6_SPI0_MASK;
mbed_official 445:3312ed629f01 40
mbed_official 445:3312ed629f01 41 obj->spi->MCR &= ~(SPI_MCR_MDIS_MASK | SPI_MCR_HALT_MASK);
mbed_official 445:3312ed629f01 42 //obj->spi->MCR |= SPI_MCR_DIS_RXF_MASK | SPI_MCR_DIS_TXF_MASK;
mbed_official 445:3312ed629f01 43
mbed_official 445:3312ed629f01 44 // not halt in the debug mode
mbed_official 445:3312ed629f01 45 obj->spi->SR |= SPI_SR_EOQF_MASK;
mbed_official 445:3312ed629f01 46
mbed_official 445:3312ed629f01 47 // pin out the spi pins
mbed_official 445:3312ed629f01 48 pinmap_pinout(mosi, PinMap_SPI_MOSI);
mbed_official 445:3312ed629f01 49 pinmap_pinout(miso, PinMap_SPI_MISO);
mbed_official 445:3312ed629f01 50 pinmap_pinout(sclk, PinMap_SPI_SCLK);
mbed_official 445:3312ed629f01 51 if (ssel != NC) {
mbed_official 445:3312ed629f01 52 pinmap_pinout(ssel, PinMap_SPI_SSEL);
mbed_official 445:3312ed629f01 53 }
mbed_official 445:3312ed629f01 54 }
mbed_official 445:3312ed629f01 55
mbed_official 445:3312ed629f01 56 void spi_free(spi_t *obj) {
mbed_official 445:3312ed629f01 57 // [TODO]
mbed_official 445:3312ed629f01 58 }
mbed_official 445:3312ed629f01 59 void spi_format(spi_t *obj, int bits, int mode, int slave) {
mbed_official 445:3312ed629f01 60 MBED_ASSERT((bits > 4) || (bits < 16));
mbed_official 445:3312ed629f01 61 MBED_ASSERT((mode >= 0) && (mode <= 3));
mbed_official 445:3312ed629f01 62
mbed_official 620:49241b7c6da5 63 uint8_t polarity = (mode & 0x2) ? 1 : 0;
mbed_official 620:49241b7c6da5 64 uint8_t phase = (mode & 0x1) ? 1 : 0;
mbed_official 620:49241b7c6da5 65 uint8_t old_polarity = (obj->spi->CTAR[0] & SPI_CTAR_CPOL_MASK) != 0;
mbed_official 445:3312ed629f01 66
mbed_official 445:3312ed629f01 67 // set master/slave
mbed_official 620:49241b7c6da5 68 if (slave) {
mbed_official 620:49241b7c6da5 69 obj->spi->MCR &= ~SPI_MCR_MSTR_MASK;
mbed_official 620:49241b7c6da5 70 } else {
mbed_official 620:49241b7c6da5 71 obj->spi->MCR |= (1UL << SPI_MCR_MSTR_SHIFT);
mbed_official 620:49241b7c6da5 72 }
mbed_official 445:3312ed629f01 73
mbed_official 445:3312ed629f01 74 // CTAR0 is used
mbed_official 445:3312ed629f01 75 obj->spi->CTAR[0] &= ~(SPI_CTAR_CPHA_MASK | SPI_CTAR_CPOL_MASK | SPI_CTAR_FMSZ_MASK);
mbed_official 445:3312ed629f01 76 obj->spi->CTAR[0] |= (polarity << SPI_CTAR_CPOL_SHIFT) | (phase << SPI_CTAR_CPHA_SHIFT) | ((bits - 1) << SPI_CTAR_FMSZ_SHIFT);
mbed_official 620:49241b7c6da5 77
mbed_official 620:49241b7c6da5 78 //If clk idle state was changed, start a dummy transmission
mbed_official 620:49241b7c6da5 79 //This is a 'feature' in DSPI: https://community.freescale.com/thread/105526
mbed_official 620:49241b7c6da5 80 if ((old_polarity != polarity) && (slave == 0)) {
mbed_official 620:49241b7c6da5 81 //Start transfer (CS should be high, so shouldn't matter)
mbed_official 620:49241b7c6da5 82 spi_master_write(obj, 0xFFFF);
mbed_official 620:49241b7c6da5 83 }
mbed_official 445:3312ed629f01 84 }
mbed_official 445:3312ed629f01 85
mbed_official 445:3312ed629f01 86 static const uint8_t baudrate_prescaler[] = {2,3,5,7};
mbed_official 445:3312ed629f01 87 static const uint16_t baudrate_scaler[] = {2,4,6,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768};
mbed_official 445:3312ed629f01 88
mbed_official 445:3312ed629f01 89 void spi_frequency(spi_t *obj, int hz) {
mbed_official 445:3312ed629f01 90 uint32_t f_error = 0;
mbed_official 445:3312ed629f01 91 uint32_t p_error = 0xffffffff;
mbed_official 445:3312ed629f01 92 uint32_t ref = 0;
mbed_official 445:3312ed629f01 93 uint32_t br = 0;
mbed_official 445:3312ed629f01 94 uint32_t ref_spr = 0;
mbed_official 445:3312ed629f01 95 uint32_t ref_prescaler = 0;
mbed_official 445:3312ed629f01 96 uint32_t ref_dr = 0;
mbed_official 445:3312ed629f01 97
mbed_official 445:3312ed629f01 98 // bus clk
mbed_official 445:3312ed629f01 99 uint32_t PCLK = bus_frequency();
mbed_official 445:3312ed629f01 100
mbed_official 445:3312ed629f01 101 for (uint32_t i = 0; i < 4; i++) {
mbed_official 445:3312ed629f01 102 for (br = 0; br <= 15; br++) {
mbed_official 445:3312ed629f01 103 for (uint32_t dr = 0; dr < 2; dr++) {
mbed_official 445:3312ed629f01 104 ref = (PCLK * (1U + dr) / baudrate_prescaler[i]) / baudrate_scaler[br];
mbed_official 445:3312ed629f01 105 if (ref > (uint32_t)hz)
mbed_official 445:3312ed629f01 106 continue;
mbed_official 445:3312ed629f01 107 f_error = hz - ref;
mbed_official 445:3312ed629f01 108 if (f_error < p_error) {
mbed_official 445:3312ed629f01 109 ref_spr = br;
mbed_official 445:3312ed629f01 110 ref_prescaler = i;
mbed_official 445:3312ed629f01 111 ref_dr = dr;
mbed_official 445:3312ed629f01 112 p_error = f_error;
mbed_official 445:3312ed629f01 113 }
mbed_official 445:3312ed629f01 114 }
mbed_official 445:3312ed629f01 115 }
mbed_official 445:3312ed629f01 116 }
mbed_official 445:3312ed629f01 117
mbed_official 445:3312ed629f01 118 // set PBR and BR
mbed_official 445:3312ed629f01 119 obj->spi->CTAR[0] &= ~(SPI_CTAR_PBR_MASK | SPI_CTAR_BR_MASK | SPI_CTAR_DBR_MASK);
mbed_official 445:3312ed629f01 120 obj->spi->CTAR[0] |= (ref_prescaler << SPI_CTAR_PBR_SHIFT) | (ref_spr << SPI_CTAR_BR_SHIFT) | (ref_dr << SPI_CTAR_DBR_SHIFT);
mbed_official 445:3312ed629f01 121 }
mbed_official 445:3312ed629f01 122
mbed_official 445:3312ed629f01 123 static inline int spi_writeable(spi_t *obj) {
mbed_official 445:3312ed629f01 124 return (obj->spi->SR & SPI_SR_TFFF_MASK) ? 1 : 0;
mbed_official 445:3312ed629f01 125 }
mbed_official 445:3312ed629f01 126
mbed_official 445:3312ed629f01 127 static inline int spi_readable(spi_t *obj) {
mbed_official 445:3312ed629f01 128 return (obj->spi->SR & SPI_SR_RFDF_MASK) ? 1 : 0;
mbed_official 445:3312ed629f01 129 }
mbed_official 445:3312ed629f01 130
mbed_official 445:3312ed629f01 131 int spi_master_write(spi_t *obj, int value) {
mbed_official 445:3312ed629f01 132 //clear RX buffer flag
mbed_official 445:3312ed629f01 133 obj->spi->SR |= SPI_SR_RFDF_MASK;
mbed_official 445:3312ed629f01 134 // wait tx buffer empty
mbed_official 445:3312ed629f01 135 while(!spi_writeable(obj));
mbed_official 445:3312ed629f01 136 obj->spi->PUSHR = SPI_PUSHR_TXDATA(value & 0xffff) /*| SPI_PUSHR_EOQ_MASK*/;
mbed_official 445:3312ed629f01 137
mbed_official 445:3312ed629f01 138 // wait rx buffer full
mbed_official 445:3312ed629f01 139 while (!spi_readable(obj));
mbed_official 445:3312ed629f01 140 return obj->spi->POPR;
mbed_official 445:3312ed629f01 141 }
mbed_official 445:3312ed629f01 142
mbed_official 445:3312ed629f01 143 int spi_slave_receive(spi_t *obj) {
mbed_official 445:3312ed629f01 144 return spi_readable(obj);
mbed_official 445:3312ed629f01 145 }
mbed_official 445:3312ed629f01 146
mbed_official 445:3312ed629f01 147 int spi_slave_read(spi_t *obj) {
mbed_official 445:3312ed629f01 148 obj->spi->SR |= SPI_SR_RFDF_MASK;
mbed_official 445:3312ed629f01 149 return obj->spi->POPR;
mbed_official 445:3312ed629f01 150 }
mbed_official 445:3312ed629f01 151
mbed_official 445:3312ed629f01 152 void spi_slave_write(spi_t *obj, int value) {
mbed_official 445:3312ed629f01 153 while (!spi_writeable(obj));
mbed_official 445:3312ed629f01 154 }