Got it! Here is the working code. The master code is on the Arduino with the SC16IS750 connected over I2C and the slave code is on the Arduino connected over TX/RX.
I remembered on my app for BLE connection on my Android phone. There was the same issue because of the limited buffer! Now I send one character after the other in both directions, because they passes the I2C connection for reading and writing. Here it is:
Master code:
/*Arduino 1 has the SC16IS750 connected on SDA/SCL
*TX/RX of the SC16IS750 is connected to Arduino 2
*VCC/GND
*I2C of the SC16IS750 is connected to VCC
*A0 and A1 of the SC16IS750 is connected as shown in the address table below
*/
#include <Wire.h>
#include <SC16IS750.h>
SC16IS750 i2cuart = SC16IS750(SC16IS750_PROTOCOL_I2C,SC16IS750_ADDRESS_AA); /*Address table: A1 A0 Address
VDD VDD 0x90 => AA
VDD GND 0x92 => AB
VDD SCL 0x94 => AC
VDD SDA 0x96 => AD
GND VDD 0x98 => BA
GND GND 0x9A => BB
GND SCL 0x9C => BC
GND SDA 0x9E => BD
SCL VDD 0xA0 => CA
SCL GND 0xA2 => CB
SCL SCL 0xA4 => CC
SCL SDA 0xA6 => CD
SDA VDD 0xA8 => DA
SDA GND 0xAA => DB
SDA SCL 0xAC => DC
SDA SDA 0xAE => DD
*/
const byte bufferSize {10};
char serialBuffer[bufferSize+1] {""};
char myData[bufferSize];
char myData1[bufferSize];
char myData2[bufferSize];
char var;
int E = 0;
int F = 0;
int G = 0;
int H = 0;
int BUT = 0;
static byte i = 0;
static byte j = 0;
static byte k = 0;
int y = 0;
void setup (void)
{
i2cuart.begin(9600);
Serial.begin(38400);
}
void loop (void)
{
Serial.print("E = ");
Serial.println(E);
Serial.print("F = ");
Serial.println(F);
Serial.print("G = ");
Serial.println(G);
Serial.print("H = ");
Serial.println(H);
Serial.print("BUT = ");
Serial.println(BUT);
command("A0");
command("B55");
command("C180");
command("D125");
command("@12");
while(i2cuart.available()) {
char m = i2cuart.read();
if(m != '\n') {
myData[i++] = m;
}
else if(m == '\n') {
i = 0;
while(i <= strlen(myData) ) {
if(isdigit(myData[i]) == true) {
myData1[j] = myData[i];
j++;
i++;
}
else {
myData2[k] = myData[i];
k++;
i++;
}
}
memset(myData, 0, sizeof myData);
j = 0;
k = 0;
i = 0;
y = atoi(myData1); //making the integer part
var = myData2[0];
memset(myData1, 0, sizeof myData1);
memset(myData2, 0, sizeof myData2);
switch(var) {
case 'E' : E = y;
break;
case 'F' : F = y;
break;
case 'G' : G = y;
break;
case 'H' : H = y;
break;
case '#' : BUT = y;
break;
}
}
}
}
void command(String value) {
memset(serialBuffer, 0, sizeof serialBuffer);
sendToSlaveI2C(serialBuffer, value);
}
void sendToSlaveI2C (char *const buffer, String command)
{
command.toCharArray(buffer, bufferSize);
const size_t numberOfChar {strlen(buffer)};
Serial.print("length: "); Serial.println(numberOfChar);
for (byte i = 0; i < numberOfChar; i++)
{
i2cuart.write(buffer[i]);
Serial.print("sent: ");
Serial.println(buffer[i]);
}
i2cuart.write('\n');
}
Slave code:
/*Arduino 2 has the SC16IS750 connected on TX/RX
*/
const byte bufferSize {10};
char serialBuffer[bufferSize+1] {""};
char myData[bufferSize];
char myData1[bufferSize];
char myData2[bufferSize];
char var;
int A = 0;
int B = 0;
int C = 0;
int D = 0;
int BUT = 0;
static byte i = 0;
static byte j = 0;
static byte k = 0;
int y = 0;
void setup()
{
Serial.begin(9600);
}
void loop() {
Serial.print("A = ");
Serial.println(A);
Serial.print("B = ");
Serial.println(B);
Serial.print("C = ");
Serial.println(C);
Serial.print("D = ");
Serial.println(D);
Serial.print("BUT = ");
Serial.println(BUT);
command("E10");
command("F5");
command("G147");
command("H251");
command("#33");
while(Serial.available()) {
char m = Serial.read();
if(m != '\n') {
myData[i++] = m;
}
else if(m == '\n') {
//Serial.print("myData: ");
//Serial.println(myData);
i = 0;
while(i <= strlen(myData) ) {
if(isdigit(myData[i]) == true) {
myData1[j] = myData[i];
j++;
i++;
}
else {
myData2[k] = myData[i];
k++;
i++;
}
}
memset(myData, 0, sizeof myData);
j = 0;
k = 0;
i = 0;
//Serial.print("myData1: ");
//Serial.println(myData1);
//Serial.print("myData2: ");
//Serial.println(myData2);
y = atoi(myData1); //making the integer part
var = myData2[0];
//Serial.println(var);
//Serial.println(y);
memset(myData1, 0, sizeof myData1);
memset(myData2, 0, sizeof myData2);
switch(var) {
case 'A' : A = y;
break;
case 'B' : B = y;
break;
case 'C' : C = y;
break;
case 'D' : D = y;
break;
case '@' : BUT = y;
break;
}
}
}
}
void command(String value) {
memset(serialBuffer, 0, sizeof serialBuffer);
sendToUART(serialBuffer, value);
}
void sendToUART (char *const buffer, String command)
{
command.toCharArray(buffer, bufferSize);
const size_t numberOfChar {strlen(buffer)};
for (byte i = 0; i < numberOfChar; i++)
{
Serial.write(buffer[i]);
}
Serial.write('\n');
}