7-Segment Display Driver class, via an 8-bit shift register (such as the 74HC595)
Diff: 7SegSRDriver.cpp
- Revision:
- 0:1832d0ed8da8
diff -r 000000000000 -r 1832d0ed8da8 7SegSRDriver.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/7SegSRDriver.cpp Sun May 01 16:13:00 2011 +0000 @@ -0,0 +1,68 @@ +#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; + } +} \ No newline at end of file