1. Introduction

This example demonstrates how to write data to a two- or four-row HD44870 LCD device on multiple platforms.

2. LCD on Various Platforms

Because each platform could have unique pins or header layouts, we show LCD on multiple platforms in the following sections.

2.1 LCD on Arduino

The Arduino is a breeze to wire up. The pin assignments are printed on the Arduino circuit board and those are the numbers used to address them in the code.

Figure 1. Arduino Wiring Diagram

This is the main program for LCD on the Arduino.

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//	[GPLv2]
// OOSMOS - The Object-Oriented State Machine Operating System
//
// Copyright (C) 2014-2020 OOSMOS, LLC
//
// This program 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, version 2 of the License ("GPLv2").
//
// This software may be used without the GPLv2 restrictions by entering
// into a commercial license agreement with OOSMOS, LLC.
// See <https://www.oosmos.com/licensing/>.
//
// This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
//

#include "oosmos.h"	#includes...
#include "pin.h"
#include "lcdtest.h"

extern void setup()
{
pin * pRS = pinNew(2, pinOut, pinActiveHigh);
pin * pE = pinNew(3, pinOut, pinActiveHigh);
pin * pData4 = pinNew(4, pinOut, pinActiveHigh);
pin * pData5 = pinNew(5, pinOut, pinActiveHigh);
pin * pData6 = pinNew(6, pinOut, pinActiveHigh);
pin * pData7 = pinNew(7, pinOut, pinActiveHigh);

lcdtestNew(pRS, pE, pData4, pData5, pData6, pData7);
}

extern void loop()
{
oosmos_RunStateMachines();
}

LcdExample.ino - LCD for Arduino

2.2 LCD on PIC32

Wiring diagram for LCD.

Figure 2. PIC32 Wiring Diagram

This is the main LCD program for the PIC32.

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//	[GPLv2]
// OOSMOS - LCD Example PIC32 main program
//
// Copyright (C) 2014-2020 OOSMOS, LLC
//
// This program 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, version 2 of the License ("GPLv2").
//
// This software may be used without the GPLv2 restrictions by entering
// into a commercial license agreement with OOSMOS, LLC.
// See <https://www.oosmos.com/licensing/>.
//
// This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
//

#include "oosmos.h"	#includes...
#include "pin.h"
#include "lcdtest.h"

#pragma config FPLLMUL = MUL_20, FPLLIDIV = DIV_2, FPLLODIV = DIV_1, FWDTEN = OFF	#pragmas...
#pragma config POSCMOD = HS, FNOSC = PRIPLL, FPBDIV = DIV_1

extern int main(void)
{
oosmos_ClockSpeedInMHz(80);

//
// Setup and drive an HD44870 LCD device.
//
pin * pRS = pinNew(IOPORT_E, BIT_0, pinOut, pinActiveHigh);
pin * pE = pinNew(IOPORT_E, BIT_1, pinOut, pinActiveHigh);
pin * pData4 = pinNew(IOPORT_E, BIT_2, pinOut, pinActiveHigh);
pin * pData5 = pinNew(IOPORT_E, BIT_3, pinOut, pinActiveHigh);
pin * pData6 = pinNew(IOPORT_E, BIT_4, pinOut, pinActiveHigh);
pin * pData7 = pinNew(IOPORT_E, BIT_5, pinOut, pinActiveHigh);

lcdtestNew(pRS, pE, pData4, pData5, pData6, pData7);

for (;;) {
oosmos_RunStateMachines();
}
}

Main program for LCD on PIC32