Kazuki Yamamoto / SWSPI

forked library from davervw/SWSPI

Dependents:   11u35_usbLocalFilesystem

Fork of SWSPI by Dave Van Wagner

SWSPI.cpp@3:8c6310f2038f, 2016-07-07 (annotated)

Committer:
k4zuki
Date:
Thu Jul 07 01:45:53 2016 +0000
Revision:
3:8c6310f2038f
Parent:
2:457a920a1223 
use all used pins as DigitalInOut to enable Hi-Z to release bus

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 3:8c6310f2038f 27 mosi = new DigitalInOut(mosi_pin);
k4zuki 3:8c6310f2038f 28 miso = new DigitalInOut(miso_pin);
k4zuki 3:8c6310f2038f 29 sclk = new DigitalInOut(sclk_pin);
k4zuki 3:8c6310f2038f 30 mosi->output();
k4zuki 3:8c6310f2038f 31 miso->input();
k4zuki 3:8c6310f2038f 32 sclk->output();
k4zuki 3:8c6310f2038f 33 format(8,0);
davervw 0:6a500a08c7fd 34 frequency();
davervw 0:6a500a08c7fd 35 }
davervw 0:6a500a08c7fd 36
davervw 0:6a500a08c7fd 37 SWSPI::~SWSPI()
davervw 0:6a500a08c7fd 38 {
davervw 0:6a500a08c7fd 39 delete mosi;
davervw 0:6a500a08c7fd 40 delete miso;
davervw 0:6a500a08c7fd 41 delete sclk;
davervw 0:6a500a08c7fd 42 }
davervw 0:6a500a08c7fd 43
davervw 0:6a500a08c7fd 44 void SWSPI::format(int bits, int mode)
davervw 0:6a500a08c7fd 45 {
davervw 0:6a500a08c7fd 46 this->bits = bits;
davervw 0:6a500a08c7fd 47 this->mode = mode;
davervw 0:6a500a08c7fd 48 polarity = (mode >> 1) & 1;
davervw 0:6a500a08c7fd 49 phase = mode & 1;
davervw 0:6a500a08c7fd 50 sclk->write(polarity);
davervw 0:6a500a08c7fd 51 }
davervw 0:6a500a08c7fd 52
davervw 0:6a500a08c7fd 53 void SWSPI::frequency(int hz)
davervw 0:6a500a08c7fd 54 {
davervw 0:6a500a08c7fd 55 this->freq = hz;
k4zuki 1:0f59aa4b839f 56 _fast = (hz >= 1000000) ? true : false;
davervw 0:6a500a08c7fd 57 }
davervw 0:6a500a08c7fd 58
k4zuki 1:0f59aa4b839f 59 #pragma Otime
k4zuki 1:0f59aa4b839f 60
davervw 0:6a500a08c7fd 61 int SWSPI::write(int value)
davervw 0:6a500a08c7fd 62 {
k4zuki 1:0f59aa4b839f 63
k4zuki 3:8c6310f2038f 64 mosi->output();
k4zuki 3:8c6310f2038f 65 miso->input();
k4zuki 3:8c6310f2038f 66 sclk->output();
davervw 0:6a500a08c7fd 67 int read = 0;
k4zuki 1:0f59aa4b839f 68 if (_fast) {
k4zuki 1:0f59aa4b839f 69 read = fast_write(value);
k4zuki 2:457a920a1223 70 } else {
k4zuki 2:457a920a1223 71 for (int bit = bits-1; bit >= 0; --bit) {
k4zuki 2:457a920a1223 72 mosi->write(((value >> bit) & 0x01) != 0);
davervw 0:6a500a08c7fd 73
k4zuki 2:457a920a1223 74 if (phase == 0) {
k4zuki 2:457a920a1223 75 if (miso->read())
k4zuki 2:457a920a1223 76 read |= (1 << bit);
k4zuki 2:457a920a1223 77 }
k4zuki 2:457a920a1223 78
k4zuki 2:457a920a1223 79 sclk->write(!polarity);
davervw 0:6a500a08c7fd 80
k4zuki 2:457a920a1223 81 wait_us(1000000/freq/2);
davervw 0:6a500a08c7fd 82
k4zuki 2:457a920a1223 83 if (phase == 1) {
k4zuki 2:457a920a1223 84 if (miso->read())
k4zuki 2:457a920a1223 85 read |= (1 << bit);
k4zuki 2:457a920a1223 86 }
k4zuki 2:457a920a1223 87
k4zuki 2:457a920a1223 88 sclk->write(polarity);
k4zuki 2:457a920a1223 89
k4zuki 2:457a920a1223 90 wait_us(1000000/freq/2);
davervw 0:6a500a08c7fd 91 }
davervw 0:6a500a08c7fd 92 }
k4zuki 3:8c6310f2038f 93 mosi->input();
k4zuki 3:8c6310f2038f 94 miso->input();
k4zuki 3:8c6310f2038f 95 sclk->input();
k4zuki 1:0f59aa4b839f 96
davervw 0:6a500a08c7fd 97 return read;
davervw 0:6a500a08c7fd 98 }
davervw 0:6a500a08c7fd 99
k4zuki 1:0f59aa4b839f 100 uint8_t SWSPI::fast_write(uint8_t value)
k4zuki 1:0f59aa4b839f 101 {
k4zuki 1:0f59aa4b839f 102 uint8_t data = 0;
k4zuki 1:0f59aa4b839f 103 for(uint8_t mask = 0x80; mask; mask >>= 1) {
k4zuki 1:0f59aa4b839f 104 mosi->write((value & mask) ? 1 : 0);
k4zuki 1:0f59aa4b839f 105 if (miso->read()) {
k4zuki 1:0f59aa4b839f 106 data |= mask;
k4zuki 1:0f59aa4b839f 107 }
k4zuki 1:0f59aa4b839f 108 sclk->write(1);
k4zuki 1:0f59aa4b839f 109 sclk->write(0);
k4zuki 1:0f59aa4b839f 110 }
k4zuki 1:0f59aa4b839f 111 return data;
k4zuki 1:0f59aa4b839f 112 }
k4zuki 1:0f59aa4b839f 113