7-Segment Display Driver class, via an 8-bit shift register (such as the 74HC595)
7SegSRDriver.cpp
- Committer:
- paul80nd
- Date:
- 2011-05-01
- Revision:
- 1:e55f543bc06b
- Parent:
- 0:1832d0ed8da8
File content as of revision 1:e55f543bc06b:
#include "mbed.h" #include "7SegSRDriver.h" /* mbed 7-Segment Display Driver Library (via an 8bit Shift Register) * Copyright (c) 2011 Paul Law * * 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. */ // Display should be hooked up to shift register as follows: // Q0 : Decimal Point, Q1-Q7 : Segments a-g SSegSRDriver::SSegSRDriver(PinName srData, PinName srClock, PinName srLatch, bool disp_type): _srData(srData), _srClock(srClock), _srLatch(srLatch) { _disp_type = disp_type; write_raw(0); } void SSegSRDriver::set_type(bool disp_type) { _disp_type = disp_type; } void SSegSRDriver::clear() { write_raw(0); } void SSegSRDriver::write(unsigned char number) { write(number,0); } void SSegSRDriver::write(unsigned char number, bool dp) { if (number<16) { // Find the definition of the number in chardefs, shift left, set dp (LSB) write_raw((SSegSRDriver_chardefs[number] << 1) | dp); } } void SSegSRDriver::write_raw(unsigned char bValue) { if (!_disp_type) bValue = ~bValue; // Reverse value for Common Anode if (bValue<=0xFF) { // Push value to shift register and latch _srLatch = 0; for (int i=7;i>=0;i--) { // Output MSB to LSB _srClock = 0; _srData = (bValue & (1<<i)); _srClock = 1; } _srLatch = 1; _srData = 0; } }