My master code now is as in post #19:
/*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 incomingData[bufferSize];
char value[bufferSize];
char variable[bufferSize];
uint16_t crc = 0; //checksum crc
byte crcData[2];
byte crcDataRec[2];
int E = 0;
int F = 0;
int G = 0;
int H = 0;
int BUT = 0;
void setup()
{
i2cuart.begin(38400);
Serial.begin(38400);
}
void loop()
{
readCommand();
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");
}
void command(String value) {
memset(serialBuffer, 0, sizeof serialBuffer);
sendToI2CUART(serialBuffer, value);
}
void sendToI2CUART (char *const buffer, String command)
{
command.toCharArray(buffer, bufferSize);
const size_t characters {strlen(buffer)};
Serial.print("length: "); Serial.println(characters);
for(byte index = 0; index < characters; index++){ //create the checksum for the array data[i] with 0 <= i <= 3
crc16(buffer[index]); //call the function crc16
}
crc = getCRC();
byte crcIndex = characters;
byte crcIndex2 = crcIndex++;
buffer[crcIndex] = crc >> 8; //store checksum in data array
buffer[crcIndex2] = crc;
for (byte i = 0; i < characters; i++)
{
i2cuart.write(buffer[i]);
Serial.print("sent: ");
Serial.println(buffer[i]);
}
i2cuart.write('\0');
i2cuart.write(buffer[crcIndex]);
Serial.println(buffer[crcIndex]);
i2cuart.write(buffer[crcIndex2]);
Serial.println(buffer[crcIndex2]);
i2cuart.write('\n');
}
//Calculates CRC16 of nBytes of data[index] in byte array
void crc16(uint8_t data) {
int i;
crc = crc ^ ((uint16_t)data << 8);
for (i=0; i<8; i++){
if (crc & 0x8000){
crc = (crc << 1) ^ 0x1021;
}
else{
crc <<= 1;
}
}
}
uint16_t getCRC() {
return crc;
}
void readCommand(){
char var;
int val = 0;
static byte i = 0;
static byte j = 0;
static byte k = 0;
byte state = 0;
while(i2cuart.available()) {
char m = i2cuart.read();
if(m == '\0') {
state = 1;
i = 0;
}
if(m == '\n') {
state = 2;
i = 0;
}
switch(state){
case 0: incomingData[i++] = m;
break;
case 1: crcData[i++] = m;
break;
case 2: for(byte index = 0; index <= strlen(incomingData); index++){ //create the checksum for the array data[i] with 0 <= i <= 3
crc16(incomingData[index]); //call the function crc16
}
crc = getCRC();
crcDataRec[0] = crc >> 8; //store checksum in data array
crcDataRec[1] = crc;
Serial.print("crcData[0] = ");
Serial.println(crcData[0]);
Serial.print("crcDataRec[0] = ");
Serial.println(crcDataRec[0]);
Serial.print("crcData[1] = ");
Serial.println(crcData[1]);
Serial.print("crcDataRec[1] = ");
Serial.println(crcDataRec[1]);
if(crcData[0] == crcDataRec[0] && crcData[1] == crcDataRec[1]) {
while(i <= strlen(incomingData) ) {
if(isdigit(incomingData[i]) == true) {
value[j] = incomingData[i];
j++;
i++;
}
else {
variable[k] = incomingData[i];
k++;
i++;
}
}
memset(incomingData, 0, sizeof incomingData);
j = 0;
k = 0;
i = 0;
val = atoi(value); //making the integer part
var = variable[0];
memset(value, 0, sizeof value);
memset(variable, 0, sizeof variable);
switch(var) {
case 'E' : E = val;
break;
case 'F' : F = val;
break;
case 'G' : G = val;
break;
case 'H' : H = val;
break;
case '#' : BUT = val;
break;
}
}
else if(crcData[0] != crcDataRec[0] || crcData[1] != crcDataRec[1]){
memset(incomingData, 0, sizeof incomingData);
}
state = 0;
}
}
}And the slave code here:
/*Arduino 2 has the SC16IS750 connected on TX/RX
*/
const byte bufferSize {10};
char serialBuffer[bufferSize+1] {""};
char incomingData[bufferSize];
char value[bufferSize];
char variable[bufferSize];
uint16_t crc = 0; //checksum crc
byte crcData[2];
byte crcDataRec[2];
int A = 0;
int B = 0;
int C = 0;
int D = 0;
int BUT = 0;
void setup()
{
Serial.begin(38400);
}
void loop() {
readCommand();
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");
}
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 characters {strlen(buffer)};
for(byte index = 0; index < characters; index++){ //create the checksum for the array data[i] with 0 <= i <= 3
crc16(buffer[index]); //call the function crc16
}
crc = getCRC();
byte crcIndex = characters;
byte crcIndex2 = crcIndex++;
buffer[crcIndex] = crc >> 8; //store checksum in data array
buffer[crcIndex2] = crc;
for (byte i = 0; i < characters; i++)
{
Serial.write(buffer[i]);
}
Serial.write('\0');
Serial.write(buffer[crcIndex]);
Serial.write(buffer[crcIndex2]);
Serial.write('\n');
}
//Calculates CRC16 of nBytes of data[index] in byte array
void crc16(uint8_t data) {
int i;
crc = crc ^ ((uint16_t)data << 8);
for (i=0; i<8; i++){
if (crc & 0x8000){
crc = (crc << 1) ^ 0x1021;
}
else{
crc <<= 1;
}
}
}
uint16_t getCRC() {
return crc;
}
void readCommand(){
char var;
int val = 0;
static byte i = 0;
static byte j = 0;
static byte k = 0;
while(Serial.available()) {
char m = Serial.read();
if(m != '\0' && m != '\n') {
incomingData[i++] = m;
}
else if(m == '\0') {
crcData[0] = Serial.read();
crcData[1] = Serial.read();
for(byte index = 0; index < i++; index++){ //create the checksum for the array data[i] with 0 <= i <= 3
crc16(incomingData[index]); //call the function crc16
}
crc = getCRC();
crcDataRec[0] = crc >> 8; //store checksum in data array
crcDataRec[1] = crc;
Serial.print("crcData[0] = ");
Serial.println(crcData[0]);
Serial.print("crcDataRec[0] = ");
Serial.println(crcDataRec[0]);
Serial.print("crcData[1] = ");
Serial.println(crcData[1]);
Serial.print("crcDataRec[1] = ");
Serial.println(crcDataRec[1]);
}
else if(m == '\n' && crcData[0] == crcDataRec[0] && crcData[1] == crcDataRec[1]) {
//Serial.print("incomingData: ");
//Serial.println(incomingData);
i = 0;
while(i <= strlen(incomingData) ) {
if(isdigit(incomingData[i]) == true) {
value[j] = incomingData[i];
j++;
i++;
}
else {
variable[k] = incomingData[i];
k++;
i++;
}
}
memset(incomingData, 0, sizeof incomingData);
j = 0;
k = 0;
i = 0;
//Serial.print("value: ");
//Serial.println(value);
//Serial.print("variable: ");
//Serial.println(variable);
val = atoi(value); //making the integer part
var = variable[0];
//Serial.println(var);
//Serial.println(val);
memset(value, 0, sizeof value);
memset(variable, 0, sizeof variable);
switch(var) {
case 'A' : A = val;
break;
case 'B' : B = val;
break;
case 'C' : C = val;
break;
case 'D' : D = val;
break;
case '@' : BUT = val;
break;
}
}
}
}The crc checksum is created with that part of code on the master and slave code:
//Calculates CRC16 of nBytes of data[index] in byte array
void crc16(uint8_t data) {
int i;
crc = crc ^ ((uint16_t)data << 8);
for (i=0; i<8; i++){
if (crc & 0x8000){
crc = (crc << 1) ^ 0x1021;
}
else{
crc <<= 1;
}
}
}The outputof the crcData and crcDataRec is individual. The crcData I show with the serial.print in the master code does not show up on the serial monitor for some reason. On the slave side the serial monitor shows up the crcData.