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CommandStation-EX/IO_OLEDDisplay.h
Neil McKechnie 47cb43d1e9 Update IO_OLEDDisplay.h
Make display updates non-blocking (after initialisation completes).
2023-02-07 23:16:00 +00:00

204 lines
6.7 KiB
C++

/*
* © 2023, Neil McKechnie. All rights reserved.
*
* This file is part of DCC++EX API
*
* This is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* It is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with CommandStation. If not, see <https://www.gnu.org/licenses/>.
*/
/*
* This driver provides a more immediate interface into the OLED display
* than the one installed through the config.h file. When an LCD(...) call
* is made, the text is output immediately to the specified display line,
* without waiting for the next 2.5 second refresh. However, if the line
* specified is off the screen then the text in the bottom line will be
* overwritten. There is however a special case that if line 255 is specified,
* the existing text will scroll up and the new line added to the bottom
* line of the screen.
*
* To install, use the following command in myHal.cpp:
* OLEDDisplay::create(address, width, height);
*
* where address is the I2C address (0x3c or 0x3d),
* width is the width in pixels of the display, and
* height is the height in pixels of the display.
*
* Valid width and height are 128x32 (SSD1306 controller),
* 128x64 (SSD1306) and 132x64 (SH1106). The driver uses
* a 5x7 character set in a 6x8 pixel cell.
*/
#ifndef IO_OLEDDISPLAY_H
#define IO_OLEDDISPLAY_H
#include "IODevice.h"
#include "DisplayInterface.h"
#include "SSD1306Ascii.h"
#include "version.h"
class OLEDDisplay : public IODevice, DisplayInterface {
private:
// Here we define the device-specific variables.
uint8_t _height; // in pixels
uint8_t _width; // in pixels
SSD1306AsciiWire *oled;
uint8_t _rowNo = 0; // Row number being written by caller
uint8_t _colNo = 0; // Position in line being written by caller
uint8_t _numRows;
uint8_t _numCols;
char *_buffer = NULL;
uint8_t *_rowGeneration = NULL;
uint8_t *_lastRowGeneration = NULL;
uint8_t _rowNoToScreen = 0;
uint8_t _charPosToScreen = 0;
public:
// Static function to handle "OLEDDisplay::create(...)" calls.
static void create(I2CAddress i2cAddress, int width = 128, int height=64) {
/* if (checkNoOverlap(i2cAddress)) */ new OLEDDisplay(i2cAddress, width, height);
}
protected:
// Constructor
OLEDDisplay(I2CAddress i2cAddress, int width, int height) {
_I2CAddress = i2cAddress;
_width = width;
_height = height;
_numCols = _width / 6; // character block 6 x 8
_numRows = _height / 8;
_charPosToScreen = _numCols;
// Allocate arrays
_buffer = (char *)calloc(_numRows*_numCols, sizeof(char));
_rowGeneration = (uint8_t *)calloc(_numRows, sizeof(uint8_t));
_lastRowGeneration = (uint8_t *)calloc(_numRows, sizeof(uint8_t));
addDevice(this);
}
// Device-specific initialisation
void _begin() override {
// Create OLED driver
oled = new SSD1306AsciiWire();
// Initialise device
if (oled->begin(_I2CAddress, _width, _height)) {
// Store pointer to this object into CS display hook, so that we
// will intercept any subsequent calls to lcdDisplay methods.
DisplayInterface::lcdDisplay = this;
DIAG(F("OLEDDisplay installed on address x%x"), (int)_I2CAddress);
// First clear the entire screen
oled->clearNative();
// Set first two lines on screen
LCD(0,F("DCC++ EX v%S"),F(VERSION));
LCD(1,F("Lic GPLv3"));
}
}
void _loop(unsigned long) override {
// Loop through the buffer and if a row has changed
// (rowGeneration[row] is changed) then start writing the
// characters from the buffer, one character per entry,
// to the screen until that row has been refreshed.
// First check if the OLED driver is still busy from a previous
// call. If so, don't to anything until the next entry.
if (!oled->isBusy()) {
// Check if we've just done the end of a row or just started
if (_charPosToScreen >= _numCols) {
// Move to next line
if (++_rowNoToScreen >= _numRows)
_rowNoToScreen = 0; // Wrap to first row
if (_rowGeneration[_rowNoToScreen] != _lastRowGeneration[_rowNoToScreen]) {
// Row content has changed, so start outputting it
_lastRowGeneration[_rowNoToScreen] = _rowGeneration[_rowNoToScreen];
oled->setRowNative(_rowNoToScreen);
_charPosToScreen = 0; // Prepare to output first character on next entry
} else {
// Row not changed, don't bother writing it.
}
} else {
// output character at current position
oled->writeNative(_buffer[_rowNoToScreen*_numCols+_charPosToScreen++]);
}
}
return;
}
/////////////////////////////////////////////////
// DisplayInterface functions
//
/////////////////////////////////////////////////
DisplayInterface* loop2(bool force) override {
(void)force; // suppress compiler warning
return NULL;
}
// Position on nominated line number (0 to number of lines -1)
// Clear the line in the buffer ready for updating
void setRow(byte line) override {
if (line == 255) {
// LCD(255, "xxx") - scroll the contents of the buffer
// and put the new line at the bottom of the screen
for (int row=1; row<_numRows; row++) {
strncpy(&_buffer[(row-1)*_numCols], &_buffer[row*_numCols], _numCols);
_rowGeneration[row-1]++;
}
line = _numRows-1;
} else if (line >= _numRows)
line = _numRows - 1; // Overwrite bottom line.
_rowNo = line;
// Fill line with blanks
for (_colNo = 0; _colNo < _numCols; _colNo++)
_buffer[_rowNo*_numCols+_colNo] = ' ';
_colNo = 0;
// Mark that the buffer has been touched. It will be
// sent to the screen on the next loop entry.
_rowGeneration[_rowNo]++;
}
// Write blanks to all of the screen (blocks until complete)
void clear () override {
// Clear buffer
for (_rowNo = 0; _rowNo < _numRows; _rowNo++) {
setRow(_rowNo);
}
_rowNo = 0;
}
// Write one character
size_t write(uint8_t c) override {
// Write character to buffer (if space)
if (_colNo < _numCols)
_buffer[_rowNo*_numCols+_colNo++] = c;
return 1;
}
// Display information about the device.
void _display() {
DIAG(F("OLEDDisplay Configured addr x%x"), (int)_I2CAddress);
}
};
#endif // IO_OLEDDISPLAY_H