wimbeaumont Project / SWSPI

sw SPI interface specific for the SOLID Slow control beta!!

Dependents:   sscm SPItest sscm

Fork of SWSPI by Dave Van Wagner

SWSPI.cpp@2:598d0028d5d2, 2014-10-02 (annotated)

Committer:
wbeaumont
Date:
Thu Oct 02 06:21:10 2014 +0000
Revision:
2:598d0028d5d2
Parent:
1:02327a96a5e2
Child:
3:9c5ae1507a81
corrected write to unsigned values

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
wbeaumont 1:02327a96a5e2 26 SWSPI::SWSPI(DigitalOut *mosi_pin, DigitalIn *miso_pin, DigitalOut *sclk_pin)
davervw 0:6a500a08c7fd 27 {
wbeaumont 1:02327a96a5e2 28 mosi = mosi_pin;
wbeaumont 1:02327a96a5e2 29 miso = miso_pin;
wbeaumont 1:02327a96a5e2 30 sclk = sclk_pin;
davervw 0:6a500a08c7fd 31 format(8);
davervw 0:6a500a08c7fd 32 frequency();
davervw 0:6a500a08c7fd 33 }
davervw 0:6a500a08c7fd 34
davervw 0:6a500a08c7fd 35 SWSPI::~SWSPI()
davervw 0:6a500a08c7fd 36 {
wbeaumont 1:02327a96a5e2 37
davervw 0:6a500a08c7fd 38 }
davervw 0:6a500a08c7fd 39
davervw 0:6a500a08c7fd 40 void SWSPI::format(int bits, int mode)
davervw 0:6a500a08c7fd 41 {
davervw 0:6a500a08c7fd 42 this->bits = bits;
davervw 0:6a500a08c7fd 43 this->mode = mode;
wbeaumont 1:02327a96a5e2 44 polarity = !((mode >> 1) & 1);
davervw 0:6a500a08c7fd 45 phase = mode & 1;
davervw 0:6a500a08c7fd 46 sclk->write(polarity);
davervw 0:6a500a08c7fd 47 }
davervw 0:6a500a08c7fd 48
davervw 0:6a500a08c7fd 49 void SWSPI::frequency(int hz)
davervw 0:6a500a08c7fd 50 {
davervw 0:6a500a08c7fd 51 this->freq = hz;
davervw 0:6a500a08c7fd 52 }
davervw 0:6a500a08c7fd 53
wbeaumont 2:598d0028d5d2 54 unsigned int SWSPI::write(unsigned int value)
davervw 0:6a500a08c7fd 55 {
davervw 0:6a500a08c7fd 56 int read = 0;
wbeaumont 2:598d0028d5d2 57 //printf("SPI write %08X ",value);
wbeaumont 1:02327a96a5e2 58 //wait(1.0/freq/2);
davervw 0:6a500a08c7fd 59 for (int bit = bits-1; bit >= 0; --bit)
davervw 0:6a500a08c7fd 60 {
wbeaumont 2:598d0028d5d2 61 mosi->write(((value >> bit) & 0x01) == 0);
davervw 0:6a500a08c7fd 62
davervw 0:6a500a08c7fd 63 if (phase == 0)
davervw 0:6a500a08c7fd 64 {
wbeaumont 2:598d0028d5d2 65 if (!miso->read())
davervw 0:6a500a08c7fd 66 read |= (1 << bit);
davervw 0:6a500a08c7fd 67 }
davervw 0:6a500a08c7fd 68
davervw 0:6a500a08c7fd 69 sclk->write(!polarity);
davervw 0:6a500a08c7fd 70
wbeaumont 1:02327a96a5e2 71 //wait(1.0/freq/2);
davervw 0:6a500a08c7fd 72
davervw 0:6a500a08c7fd 73 if (phase == 1)
davervw 0:6a500a08c7fd 74 {
wbeaumont 2:598d0028d5d2 75 if (!miso->read())
davervw 0:6a500a08c7fd 76 read |= (1 << bit);
davervw 0:6a500a08c7fd 77 }
davervw 0:6a500a08c7fd 78
davervw 0:6a500a08c7fd 79 sclk->write(polarity);
davervw 0:6a500a08c7fd 80
wbeaumont 1:02327a96a5e2 81 //wait(1.0/freq/2);
davervw 0:6a500a08c7fd 82 }
wbeaumont 2:598d0028d5d2 83 //printf(" SPIR reads %08X \n\r" , read);
davervw 0:6a500a08c7fd 84 return read;
davervw 0:6a500a08c7fd 85 }
davervw 0:6a500a08c7fd 86