Kazuki Yamamoto / SWSPI

forked library from davervw/SWSPI

Dependents:   11u35_usbLocalFilesystem

Fork of SWSPI by Dave Van Wagner

SWSPI.cpp@2:457a920a1223, 2016-03-04 (annotated)

Committer:
k4zuki
Date:
Fri Mar 04 10:33:56 2016 +0000
Revision:
2:457a920a1223
Parent:
1:0f59aa4b839f
Child:
3:8c6310f2038f
update

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 "SWSPI.h"
davervw 0:6a500a08c7fd 24
k4zuki 1:0f59aa4b839f 25 SWSPI::SWSPI(PinName mosi_pin, PinName miso_pin, PinName sclk_pin):_fast(false)
davervw 0:6a500a08c7fd 26 {
k4zuki 2:457a920a1223 27 mosi = new DigitalOut(mosi_pin);
k4zuki 2:457a920a1223 28 miso = new DigitalIn(miso_pin);
k4zuki 2:457a920a1223 29 sclk = new DigitalOut(sclk_pin);
davervw 0:6a500a08c7fd 30 format(8);
davervw 0:6a500a08c7fd 31 frequency();
davervw 0:6a500a08c7fd 32 }
davervw 0:6a500a08c7fd 33
davervw 0:6a500a08c7fd 34 SWSPI::~SWSPI()
davervw 0:6a500a08c7fd 35 {
davervw 0:6a500a08c7fd 36 delete mosi;
davervw 0:6a500a08c7fd 37 delete miso;
davervw 0:6a500a08c7fd 38 delete sclk;
davervw 0:6a500a08c7fd 39 }
davervw 0:6a500a08c7fd 40
davervw 0:6a500a08c7fd 41 void SWSPI::format(int bits, int mode)
davervw 0:6a500a08c7fd 42 {
davervw 0:6a500a08c7fd 43 this->bits = bits;
davervw 0:6a500a08c7fd 44 this->mode = mode;
davervw 0:6a500a08c7fd 45 polarity = (mode >> 1) & 1;
davervw 0:6a500a08c7fd 46 phase = mode & 1;
davervw 0:6a500a08c7fd 47 sclk->write(polarity);
davervw 0:6a500a08c7fd 48 }
davervw 0:6a500a08c7fd 49
davervw 0:6a500a08c7fd 50 void SWSPI::frequency(int hz)
davervw 0:6a500a08c7fd 51 {
davervw 0:6a500a08c7fd 52 this->freq = hz;
k4zuki 1:0f59aa4b839f 53 _fast = (hz >= 1000000) ? true : false;
davervw 0:6a500a08c7fd 54 }
davervw 0:6a500a08c7fd 55
k4zuki 1:0f59aa4b839f 56 #pragma Otime
k4zuki 1:0f59aa4b839f 57
davervw 0:6a500a08c7fd 58 int SWSPI::write(int value)
davervw 0:6a500a08c7fd 59 {
k4zuki 1:0f59aa4b839f 60
davervw 0:6a500a08c7fd 61 int read = 0;
k4zuki 1:0f59aa4b839f 62 if (_fast) {
k4zuki 1:0f59aa4b839f 63 read = fast_write(value);
k4zuki 2:457a920a1223 64 } else {
k4zuki 2:457a920a1223 65 for (int bit = bits-1; bit >= 0; --bit) {
k4zuki 2:457a920a1223 66 mosi->write(((value >> bit) & 0x01) != 0);
davervw 0:6a500a08c7fd 67
k4zuki 2:457a920a1223 68 if (phase == 0) {
k4zuki 2:457a920a1223 69 if (miso->read())
k4zuki 2:457a920a1223 70 read |= (1 << bit);
k4zuki 2:457a920a1223 71 }
k4zuki 2:457a920a1223 72
k4zuki 2:457a920a1223 73 sclk->write(!polarity);
davervw 0:6a500a08c7fd 74
k4zuki 2:457a920a1223 75 wait_us(1000000/freq/2);
davervw 0:6a500a08c7fd 76
k4zuki 2:457a920a1223 77 if (phase == 1) {
k4zuki 2:457a920a1223 78 if (miso->read())
k4zuki 2:457a920a1223 79 read |= (1 << bit);
k4zuki 2:457a920a1223 80 }
k4zuki 2:457a920a1223 81
k4zuki 2:457a920a1223 82 sclk->write(polarity);
k4zuki 2:457a920a1223 83
k4zuki 2:457a920a1223 84 wait_us(1000000/freq/2);
davervw 0:6a500a08c7fd 85 }
davervw 0:6a500a08c7fd 86 }
k4zuki 1:0f59aa4b839f 87
davervw 0:6a500a08c7fd 88 return read;
davervw 0:6a500a08c7fd 89 }
davervw 0:6a500a08c7fd 90
k4zuki 1:0f59aa4b839f 91 uint8_t SWSPI::fast_write(uint8_t value)
k4zuki 1:0f59aa4b839f 92 {
k4zuki 1:0f59aa4b839f 93 uint8_t data = 0;
k4zuki 1:0f59aa4b839f 94 for(uint8_t mask = 0x80; mask; mask >>= 1) {
k4zuki 1:0f59aa4b839f 95 mosi->write((value & mask) ? 1 : 0);
k4zuki 1:0f59aa4b839f 96 if (miso->read()) {
k4zuki 1:0f59aa4b839f 97 data |= mask;
k4zuki 1:0f59aa4b839f 98 }
k4zuki 1:0f59aa4b839f 99 sclk->write(1);
k4zuki 1:0f59aa4b839f 100 sclk->write(0);
k4zuki 1:0f59aa4b839f 101 }
k4zuki 1:0f59aa4b839f 102 return data;
k4zuki 1:0f59aa4b839f 103 }
k4zuki 1:0f59aa4b839f 104