Kazuki Yamamoto / SWSPI

forked library from davervw/SWSPI

Dependents:   11u35_usbLocalFilesystem

Fork of SWSPI by Dave Van Wagner

SWSPI.cpp@1:0f59aa4b839f, 2015-10-06 (annotated)

Committer:
k4zuki
Date:
Tue Oct 06 02:12:46 2015 +0000
Revision:
1:0f59aa4b839f
Parent:
0:6a500a08c7fd
Child:
2:457a920a1223
fork from davervw/SWSPI

Who changed what in which revision?

UserRevisionLine numberNew contents of line
davervw 0:6a500a08c7fd 1 /* SWSPI, Software SPI library
davervw 0:6a500a08c7fd 2 * Copyright (c) 2012-2014, David R. Van Wagner, http://techwithdave.blogspot.com
davervw 0:6a500a08c7fd 3 *
davervw 0:6a500a08c7fd 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
davervw 0:6a500a08c7fd 5 * of this software and associated documentation files (the "Software"), to deal
davervw 0:6a500a08c7fd 6 * in the Software without restriction, including without limitation the rights
davervw 0:6a500a08c7fd 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
davervw 0:6a500a08c7fd 8 * copies of the Software, and to permit persons to whom the Software is
davervw 0:6a500a08c7fd 9 * furnished to do so, subject to the following conditions:
davervw 0:6a500a08c7fd 10 *
davervw 0:6a500a08c7fd 11 * The above copyright notice and this permission notice shall be included in
davervw 0:6a500a08c7fd 12 * all copies or substantial portions of the Software.
davervw 0:6a500a08c7fd 13 *
davervw 0:6a500a08c7fd 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
davervw 0:6a500a08c7fd 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
davervw 0:6a500a08c7fd 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
davervw 0:6a500a08c7fd 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
davervw 0:6a500a08c7fd 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
davervw 0:6a500a08c7fd 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
davervw 0:6a500a08c7fd 20 * THE SOFTWARE.
davervw 0:6a500a08c7fd 21 */
davervw 0:6a500a08c7fd 22
davervw 0:6a500a08c7fd 23 #include <mbed.h>
davervw 0:6a500a08c7fd 24 #include "SWSPI.h"
davervw 0:6a500a08c7fd 25
k4zuki 1:0f59aa4b839f 26 SWSPI::SWSPI(PinName mosi_pin, PinName miso_pin, PinName sclk_pin):_fast(false)
davervw 0:6a500a08c7fd 27 {
k4zuki 1:0f59aa4b839f 28 mosi = new DigitalInOut(mosi_pin);
k4zuki 1:0f59aa4b839f 29 mosi->input();
k4zuki 1:0f59aa4b839f 30 mosi->mode(PullNone);
k4zuki 1:0f59aa4b839f 31 miso = new DigitalInOut(miso_pin);
k4zuki 1:0f59aa4b839f 32 miso->input();
k4zuki 1:0f59aa4b839f 33 miso->mode(PullNone);
k4zuki 1:0f59aa4b839f 34 sclk = new DigitalInOut(sclk_pin);
k4zuki 1:0f59aa4b839f 35 sclk->input();
k4zuki 1:0f59aa4b839f 36 sclk->mode(PullNone);
davervw 0:6a500a08c7fd 37 format(8);
davervw 0:6a500a08c7fd 38 frequency();
davervw 0:6a500a08c7fd 39 }
davervw 0:6a500a08c7fd 40
davervw 0:6a500a08c7fd 41 SWSPI::~SWSPI()
davervw 0:6a500a08c7fd 42 {
davervw 0:6a500a08c7fd 43 delete mosi;
davervw 0:6a500a08c7fd 44 delete miso;
davervw 0:6a500a08c7fd 45 delete sclk;
davervw 0:6a500a08c7fd 46 }
davervw 0:6a500a08c7fd 47
davervw 0:6a500a08c7fd 48 void SWSPI::format(int bits, int mode)
davervw 0:6a500a08c7fd 49 {
davervw 0:6a500a08c7fd 50 this->bits = bits;
davervw 0:6a500a08c7fd 51 this->mode = mode;
davervw 0:6a500a08c7fd 52 polarity = (mode >> 1) & 1;
davervw 0:6a500a08c7fd 53 phase = mode & 1;
davervw 0:6a500a08c7fd 54 sclk->write(polarity);
davervw 0:6a500a08c7fd 55 }
davervw 0:6a500a08c7fd 56
davervw 0:6a500a08c7fd 57 void SWSPI::frequency(int hz)
davervw 0:6a500a08c7fd 58 {
davervw 0:6a500a08c7fd 59 this->freq = hz;
k4zuki 1:0f59aa4b839f 60 _fast = (hz >= 1000000) ? true : false;
davervw 0:6a500a08c7fd 61 }
davervw 0:6a500a08c7fd 62
k4zuki 1:0f59aa4b839f 63 #pragma Otime
k4zuki 1:0f59aa4b839f 64
davervw 0:6a500a08c7fd 65 int SWSPI::write(int value)
davervw 0:6a500a08c7fd 66 {
k4zuki 1:0f59aa4b839f 67 mosi->output();
k4zuki 1:0f59aa4b839f 68 mosi->mode(PullNone);
k4zuki 1:0f59aa4b839f 69 miso->input();
k4zuki 1:0f59aa4b839f 70 miso->mode(PullNone);
k4zuki 1:0f59aa4b839f 71 sclk->output();
k4zuki 1:0f59aa4b839f 72 sclk->mode(PullNone);
k4zuki 1:0f59aa4b839f 73
davervw 0:6a500a08c7fd 74 int read = 0;
k4zuki 1:0f59aa4b839f 75 if (_fast) {
k4zuki 1:0f59aa4b839f 76 read = fast_write(value);
k4zuki 1:0f59aa4b839f 77 }
davervw 0:6a500a08c7fd 78 for (int bit = bits-1; bit >= 0; --bit)
davervw 0:6a500a08c7fd 79 {
davervw 0:6a500a08c7fd 80 mosi->write(((value >> bit) & 0x01) != 0);
davervw 0:6a500a08c7fd 81
davervw 0:6a500a08c7fd 82 if (phase == 0)
davervw 0:6a500a08c7fd 83 {
davervw 0:6a500a08c7fd 84 if (miso->read())
davervw 0:6a500a08c7fd 85 read |= (1 << bit);
davervw 0:6a500a08c7fd 86 }
davervw 0:6a500a08c7fd 87
davervw 0:6a500a08c7fd 88 sclk->write(!polarity);
davervw 0:6a500a08c7fd 89
k4zuki 1:0f59aa4b839f 90 wait_us(1000000/freq/2);
davervw 0:6a500a08c7fd 91
davervw 0:6a500a08c7fd 92 if (phase == 1)
davervw 0:6a500a08c7fd 93 {
davervw 0:6a500a08c7fd 94 if (miso->read())
davervw 0:6a500a08c7fd 95 read |= (1 << bit);
davervw 0:6a500a08c7fd 96 }
davervw 0:6a500a08c7fd 97
davervw 0:6a500a08c7fd 98 sclk->write(polarity);
davervw 0:6a500a08c7fd 99
k4zuki 1:0f59aa4b839f 100 wait_us(1000000/freq/2);
davervw 0:6a500a08c7fd 101 }
k4zuki 1:0f59aa4b839f 102
k4zuki 1:0f59aa4b839f 103 mosi->input();
k4zuki 1:0f59aa4b839f 104 mosi->mode(PullNone);
k4zuki 1:0f59aa4b839f 105 miso->input();
k4zuki 1:0f59aa4b839f 106 miso->mode(PullNone);
k4zuki 1:0f59aa4b839f 107 sclk->input();
k4zuki 1:0f59aa4b839f 108 sclk->mode(PullNone);
davervw 0:6a500a08c7fd 109
davervw 0:6a500a08c7fd 110 return read;
davervw 0:6a500a08c7fd 111 }
davervw 0:6a500a08c7fd 112
k4zuki 1:0f59aa4b839f 113 uint8_t SWSPI::fast_write(uint8_t value)
k4zuki 1:0f59aa4b839f 114 {
k4zuki 1:0f59aa4b839f 115 uint8_t data = 0;
k4zuki 1:0f59aa4b839f 116 for(uint8_t mask = 0x80; mask; mask >>= 1) {
k4zuki 1:0f59aa4b839f 117 mosi->write((value & mask) ? 1 : 0);
k4zuki 1:0f59aa4b839f 118 if (miso->read()) {
k4zuki 1:0f59aa4b839f 119 data |= mask;
k4zuki 1:0f59aa4b839f 120 }
k4zuki 1:0f59aa4b839f 121 sclk->write(1);
k4zuki 1:0f59aa4b839f 122 sclk->write(0);
k4zuki 1:0f59aa4b839f 123 }
k4zuki 1:0f59aa4b839f 124 return data;
k4zuki 1:0f59aa4b839f 125 }
k4zuki 1:0f59aa4b839f 126