Half Duplex Version of SWSPI
Fork of SWSPI by
SWSPI_HD.cpp
- Committer:
- martinsimpson
- Date:
- 2018-06-19
- Revision:
- 3:d3be72ac889e
- Parent:
- 2:70039cc8ba02
File content as of revision 3:d3be72ac889e:
/* SWSPI, Software SPI library * Copyright (c) 2012-2014, David R. Van Wagner, http://techwithdave.blogspot.com * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include <mbed.h> #include "SWSPI_HD.h" SWSPI_HD::SWSPI_HD(PinName dio_pin, PinName sclk_pin, PinName cs_pin) { dio = new DigitalInOut(dio_pin); sclk = new DigitalOut(sclk_pin); cs = new DigitalOut(cs_pin,true); format(8); frequency(); } SWSPI_HD::~SWSPI_HD() { delete dio; delete sclk; delete cs; } void SWSPI_HD::format(int bits, int mode) { this->bits = bits; this->mode = mode; polarity = (mode >> 1) & 1; phase = mode & 1; sclk->write(polarity); } void SWSPI_HD::frequency(int hz) { this->freq = hz; } int SWSPI_HD::write(int value) { int read = 0; //ensure clock is in right phase to start and disable slave device cs->write(true); sclk->write(!polarity); //Write Out dio->output();// set as an OUTPUT cs->write(false);//select slave device (active low) for (int bit = bits-1; bit >= 0; --bit) { dio->write(((value >> bit) & 0x01) != 0); wait(1.0/freq/2); sclk->write(!polarity); wait(1.0/freq/2); sclk->write(polarity); } //Read In dio->input();// set as an INPUT for (int bit = bits-1; bit >= 0; --bit) { if (phase == 0) { if (dio->read()) // was miso read |= (1 << bit); } sclk->write(!polarity); wait(1.0/freq/2); if (phase == 1) { if (dio->read()) // was miso read |= (1 << bit); } sclk->write(polarity); wait(1.0/freq/2); } cs->write(true); return read; }