Software SPI allows non-standard SPI pins to be used for interfacing with SPI devices
Fork of SWSPI by
SWSPI.cpp
- Committer:
- lionello
- Date:
- 2015-05-08
- Revision:
- 2:eafe3ec5fbf8
- Parent:
- 1:9e0c0217646d
- Child:
- 3:8c19911bdb58
File content as of revision 2:eafe3ec5fbf8:
/* 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.h" SWSPI::SWSPI(PinName mosi_pin, PinName miso_pin, PinName sclk_pin) : mosi(mosi_pin), miso(NULL), sclk(sclk_pin) { if (miso_pin!= NC) miso = new DigitalIn(miso_pin); format(8); frequency(); } SWSPI::~SWSPI() { delete miso; } void SWSPI::format(int bits, int mode) { this->bits = bits; polarity = (mode >> 1) & 1; phase = mode & 1; sclk.write(polarity); } void SWSPI::frequency(int hz) { // TODO: need wait_ns taking int this->delay_s = 0.5f/hz; } int SWSPI::write(int value) { int read = 0; for (unsigned bit = 1 << (bits-1); bit; bit >>= 1) { mosi.write((value & bit) != 0); if (phase == 0) { if (miso && miso->read()) read |= (1 << bit); } sclk.write(!polarity); wait(delay_s); if (phase == 1) { if (miso && miso->read()) read |= (1 << bit); } sclk.write(polarity); wait(delay_s); } return read; }