Skip to content

Add LCD Variables Display Support #31

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
mat100 wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Add LCD Variables Display Support #31

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
546935f
Added support for displaying variables from LinuxCNC on an LCD connec…
mat100 Aug 16, 2025
0f11c37
Fix LCD int/bool vars and add display image to README
mat100 Aug 17, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
258 changes: 245 additions & 13 deletions LinuxCNC_ArduinoConnector.ino
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,3 +1,10 @@
//#include <Arduino.h>
//#include <stdlib.h>
//#include <ctype.h>
//#include <LiquidCrystal.h>
//#include <math.h>
//#include <string.h>

/*
LinuxCNC_ArduinoConnector
By Alexander Richter, [email protected] 2022
Expand Down Expand Up @@ -35,6 +42,11 @@
joystick = 'R' -write only -Pin State: up/ down / -2147483648 to 2147483647
multiplexed LEDs = 'M' -read only -Pin State: 0,1

LCD Variables:
LCD Float Variables = 'F' -write only -Pin State: integer (×1000)
LCD Integer Variables = 'N' -write only -Pin State: integer value
LCD Boolean Variables = 'B' -write only -Pin State: 0,1

Keyboard Input:
Matrix Keypad = 'M' -write only -Pin State: 0,1

Expand Down Expand Up @@ -302,7 +314,73 @@ int currentLED = 0;
#endif



//#define LCD_VARS
#ifdef LCD_VARS
// LCD Display Configuration
#define LCD_COLUMNS 20
#define LCD_ROWS 4

// LCD Pin definitions
#define LCD_PINS_RS 82
#define LCD_PINS_ENABLE 61
#define LCD_PINS_D4 59
#define LCD_PINS_D5 70
#define LCD_PINS_D6 85
#define LCD_PINS_D7 71

// LCD object initialization
LiquidCrystal lcd(LCD_PINS_RS, LCD_PINS_ENABLE, LCD_PINS_D4, LCD_PINS_D5, LCD_PINS_D6, LCD_PINS_D7);

// Variable types
enum VarType {
VAR_FLOAT,
VAR_INT,
VAR_BOOL
};

// Structure for variable definition
struct LCDVar {
const char* name; // Variable name
uint8_t row; // Row on LCD (0-3)
uint8_t col; // Column on LCD (0-19)
VarType type; // Variable type
union {
float floatValue; // For float variables
int32_t intValue; // For int variables
bool boolValue; // For bool variables
} value;
union {
float floatOldValue; // For float variables
int32_t intOldValue; // For int variables
bool boolOldValue; // For bool variables
} oldValue;
uint8_t decimals; // Number of decimal places (for float)
};

// Macros to simplify LCD variable definitions
#define LCD_FLOAT(name, row, col, decimals) {name, row, col, VAR_FLOAT, {.floatValue = 0.0}, {.floatOldValue = -999.0}, decimals}
#define LCD_INT(name, row, col) {name, row, col, VAR_INT, {.intValue = 0}, {.intOldValue = -999}, 0}
#define LCD_BOOL(name, row, col) {name, row, col, VAR_BOOL, {.boolValue = false}, {.boolOldValue = false}, 0}

// Variable definitions - modify as needed
LCDVar lcdVars[] = {
LCD_FLOAT("Float var 1: ", 0, 0, 3), // on row 0, column 0, 3 decimal place
LCD_FLOAT("Float var 2: ", 1, 0, 2), // on row 1, column 0, 2 decimal places
LCD_INT("Int var: ", 2, 0),
LCD_BOOL("Bool var: ", 3, 0)
};

// Macro to calculate the number of variables
#define LCD_VAR_COUNT (sizeof(lcdVars) / sizeof(lcdVars[0]))

// Function to initialize LCD variables
void initLCDVars();

// Function to set LCD variable value from LinuxCNC
void setLCDVar(int index, float newValue);
void setLCDVar(int index, int32_t newValue);
void setLCDVar(int index, bool newValue);
#endif

//#define DEBUG
//####################################### END OF CONFIG ###########################
Expand Down Expand Up @@ -391,15 +469,15 @@ int connectionState = 0;


byte state = STATE_CMD;
char inputbuffer[5];
char inputbuffer[32]; // Increased size for large float values (e.g., 123400)
byte bufferIndex = 0;
char cmd = 0;
uint16_t io = 0;
uint16_t value = 0;
int32_t value = 0; // Changed from uint16_t to int32_t for LCD float values

// Function Prototypes
void readCommands();
void commandReceived(char cmd, uint16_t io, uint16_t value);
void commandReceived(char cmd, uint16_t io, int32_t value);
void multiplexLeds();
void readKeypad();
int readAbsKnob();
Expand Down Expand Up @@ -483,8 +561,16 @@ for(int col = 0; col < numCols; col++) {
}
#endif

#ifdef LCD_VARS
lcd.begin(LCD_COLUMNS, LCD_ROWS);
lcd.clear();
// Initialize LCD variables
initLCDVars();

//Setup Serial
delay(500);
#endif

//Setup Serial
Serial.begin(115200);
while (!Serial){}
comalive();
Expand Down Expand Up @@ -999,7 +1085,116 @@ void multiplexLeds() {
}
#endif

void commandReceived(char cmd, uint16_t io, uint16_t value){
#ifdef LCD_VARS

void initLCDVars() {
for (size_t i = 0; i < LCD_VAR_COUNT; i++) {
lcd.setCursor(lcdVars[i].col, lcdVars[i].row);
lcd.print(lcdVars[i].name);
// Clear the rest of the line
int spacesToClear = LCD_COLUMNS - (lcdVars[i].col + strlen(lcdVars[i].name));
if (spacesToClear > 0) {
for (int j = 0; j < spacesToClear; j++) {
lcd.print(" ");
}
}
}
}

void setLCDVar(int index, float newValue) {
// Set float variable value received from LinuxCNC
if (index >= 0 && (size_t)index < LCD_VAR_COUNT && lcdVars[index].type == VAR_FLOAT) {
lcdVars[index].value.floatValue = newValue;

#ifdef DEBUG
Serial.print("Float var ");
Serial.print(index);
Serial.print(" set to: ");
Serial.println(newValue);
#endif

// Check if value changed - compare newValue with oldValue
bool valueChanged = (newValue != lcdVars[index].oldValue.floatOldValue);
// Update LCD display if value changed
if (valueChanged) {
lcd.setCursor(lcdVars[index].col, lcdVars[index].row);
lcd.print(lcdVars[index].name);
lcd.print(lcdVars[index].value.floatValue, lcdVars[index].decimals);
// Clear the rest of the line
int spacesToClear = LCD_COLUMNS - (lcdVars[index].col + strlen(lcdVars[index].name) + String(lcdVars[index].value.floatValue, lcdVars[index].decimals).length());
if (spacesToClear > 0) {
for (int j = 0; j < spacesToClear; j++) {
lcd.print(" ");
}
}
lcdVars[index].oldValue.floatOldValue = newValue;
}
}
}

void setLCDVar(int index, int32_t newValue) {
if (index >= 0 && (size_t)index < LCD_VAR_COUNT && lcdVars[index].type == VAR_INT) {
lcdVars[index].value.intValue = newValue;

#ifdef DEBUG
Serial.print("Int var ");
Serial.print(index);
Serial.print(" set to: ");
Serial.println(newValue);
#endif

// Check if value changed - compare newValue with oldValue
bool valueChanged = (newValue != lcdVars[index].oldValue.intOldValue);
// Update LCD display if value changed
if (valueChanged) {
lcd.setCursor(lcdVars[index].col, lcdVars[index].row);
lcd.print(lcdVars[index].name);
lcd.print(lcdVars[index].value.intValue);
// Clear the rest of the line
int spacesToClear = LCD_COLUMNS - (lcdVars[index].col + strlen(lcdVars[index].name) + String(lcdVars[index].value.intValue).length());
if (spacesToClear > 0) {
for (int j = 0; j < spacesToClear; j++) {
lcd.print(" ");
}
}
lcdVars[index].oldValue.intOldValue = newValue;
}
}
}

void setLCDVar(int index, bool newValue) {
if (index >= 0 && (size_t)index < LCD_VAR_COUNT && lcdVars[index].type == VAR_BOOL) {
lcdVars[index].value.boolValue = newValue;

#ifdef DEBUG
Serial.print("Bool var ");
Serial.print(index);
Serial.print(" set to: ");
Serial.println(newValue);
#endif

// Check if value changed - compare newValue with oldValue
bool valueChanged = (newValue != lcdVars[index].oldValue.boolOldValue);
// Update LCD display if value changed
if (valueChanged) {
lcd.setCursor(lcdVars[index].col, lcdVars[index].row);
lcd.print(lcdVars[index].name);
lcd.print(lcdVars[index].value.boolValue ? "ON " : "OFF");
// Clear the rest of the line - FIXED: Both "ON " and "OFF" are 3 characters
int spacesToClear = LCD_COLUMNS - (lcdVars[index].col + strlen(lcdVars[index].name) + 3);
if (spacesToClear > 0) {
for (int j = 0; j < spacesToClear; j++) {
lcd.print(" ");
}
}
lcdVars[index].oldValue.boolOldValue = newValue;
}
}
}

#endif // LCD_VARS

void commandReceived(char cmd, uint16_t io, int32_t value){
#ifdef OUTPUTS
if(cmd == 'O'){
writeOutputs(io,value);
Expand Down Expand Up @@ -1041,6 +1236,41 @@ void commandReceived(char cmd, uint16_t io, uint16_t value){
}
#endif

#ifdef LCD_VARS
if(cmd == 'F'){ // Set float variable from LinuxCNC
// io = index of variable, value = integer part (multiplied by 1000)
// Convert back to float by dividing by 1000
float floatValue = (float)value / 1000.0;
setLCDVar(io, floatValue);
lastcom=millis();
}
if(cmd == 'N'){ // Set integer variable from LinuxCNC
// io = index of variable, value = integer value
int32_t intValue = (int32_t)value;
#ifdef DEBUG
Serial.print("Received INT command N");
Serial.print(io);
Serial.print(":");
Serial.println(intValue);
#endif
setLCDVar(io, intValue);
lastcom=millis();
}
if(cmd == 'B'){ // Set boolean variable from LinuxCNC
// io = index of variable, value = boolean value (0 or 1)
bool boolValue = (value != 0);
#ifdef DEBUG
Serial.print("Received BOOL command B");
Serial.print(io);
Serial.print(":");
Serial.print(value);
Serial.print(" -> ");
Serial.println(boolValue ? "ON" : "OFF");
#endif
setLCDVar(io, boolValue);
lastcom=millis();
}
#endif

if(cmd == 'E'){
lastcom=millis();
Expand Down Expand Up @@ -1071,35 +1301,37 @@ void readCommands(){
bufferIndex = 0;
break;
case STATE_IO:
if(isDigit(current)){
if(isdigit(current)){ // Only accept digits for pin/index
inputbuffer[bufferIndex++] = current;
}else if(current == ':'){
inputbuffer[bufferIndex] = 0;
io = atoi(inputbuffer);
io = strtol(inputbuffer, NULL, 10);
state = STATE_VALUE;
bufferIndex = 0;

}
else{
#ifdef DEBUG
Serial.print("Ungültiges zeichen: ");
Serial.print("Invalid character: ");
Serial.println(current);
#endif
}
break;
case STATE_VALUE:
if(isDigit(current)){
inputbuffer[bufferIndex++] = current;
if(isdigit(current) || current == '-'){ // Accept digits and minus sign
if(bufferIndex < 31) { // Prevent buffer overflow
inputbuffer[bufferIndex++] = current;
}
}
else if(current == '\n'){
inputbuffer[bufferIndex] = 0;
value = atoi(inputbuffer);
value = strtol(inputbuffer, NULL, 10); // Use strtol() for better int32_t parsing
commandReceived(cmd, io, value);
state = STATE_CMD;
}
else{
#ifdef DEBUG
Serial.print("Ungültiges zeichen: ");
Serial.print("Invalid character: ");
Serial.println(current);
#endif

Expand Down
Loading