NANO RP2040 CONNECT need more Serial Comms

[jhaytera]

I'm using Serial and Serial1 with my NANO RP2040 CONNECT, and need more serial ports. Is it possible?

[Whandall]

One software serial should be possible,
and there are also UART expansions, that can be addressed via SPI/I2C.

SC16IS752 IIC I2C/SPI Bus Interface Dual UART
https://de.aliexpress.com/item/1005004556856100.html

[jhaytera]

I bought a Portenta H7 and the associated Portenta Breakout Board. I am very pleased. I have four UARTs running at 1M baud. That's seperate from the programming port I have running at 2M baud.

I modified code from some excellent work found at:
Portenta Serial UART - four easy ports separate from the programming port

My Portenta UART test Sketch:

/* Portenta Serial UART


* Code modified from:
Thank you, Jeremy Ellis!
https://github.com/hpssjellis/portenta-pro-community-solutions/blob/main/examples/dot1-portentaH7-examples/dot19-cores-uart-serial-com/dot198-uart-serialtransfer/dot198-uart-serialtransfer.ino


* Code modified from:
Thank you, Jeremy Ellis!
//This, go there... ---> https://github.com/hpssjellis/portenta-pro-community-solutions

* ================================================================================
* For this program
* 
* 1 way
* Connect (sender) myUART6 pin D5 TX to (receiver) myUART8 pin D6 RX 
* 
* 
* If you wanted to do 2 way
* Connect Serial1 pin D14 TX to myUART6 pin D4 RX 
* Connect Serial1 pin D13 RX to myUART6 pin D5 TX 
* 
* 
* Then load serial monitor, change delay to speed up
* 
* ================================================================================
* 
* * UART Information for the PortentaH7 
* 
* UART myUART0(PA_0,  PI_9,  NC, NC);  // TX, RX, RTS, CTC  NOTE: NC means not connected
* UART myUART1(PA_9,  PA_10, NC, NC);   // pin D14 TX, pin D13 RX same as pre-defined Serial1
* UART myUART2(PG_14, PG_9,  NC, NC);
* UART myUART3(PJ_8,  PJ_9,  NC, NC);
* UART myUART6(PC_6,  PC_7, NC, NC);    // pin D5 TX, pin D4 RX
* UART myUART8(NC,    PA_8, NC, NC);    // pin D6 RX only can receive
* 
*/

//#include <Arduino.h>
//#include <Arduino_PortentaBreakout.h>
//#include "SerialTransfer.h"

//////////////////// Start All Core M7 Programing /////////////////////
#ifdef CORE_CM7 


//--------------------------------------------- NOTE ------------------------------------------------------
// I used the Portenta Breakout Board and soldred some jumpers on the four UART breakouts. 
// Everything worked.
//
// UART Test1 is a bidirectional test of UART0 and UART1
// UART Test2 is a bidirectional test of UART2 and UART3


//--assign Serial UART
//https://github.com/hpssjellis/portenta-pro-community-solutions <--- Most excellent URL
//Thank you, Jeremy Ellis!
//UART myUART0(PA_0,  PI_9,  NC, NC); // put this back to test with with myUART1 on M4 Test1 - worked 20230218  
UART myUART2(PG_14, PG_9,  NC, NC); // put this back to test with with myUART3 on M4 Test2 - worked 20230218  

int i=65; //(char)"A";

void setup() { 
  pinMode(LEDR, OUTPUT);   // LEDB = blue, LEDG or LED_BUILTIN = green, LEDR = red 
   bootM4();    
   Serial.begin(2000000);

   //myUART0.begin(1000000);   
   //myUART0.setTimeout(10);
   myUART2.begin(1000000);   
   myUART2.setTimeout(10);
}

void loop() {
  if (i > 90){i = 65;}           // ascii 65 =  letter A,   ascii 90 = letter Z
  //myUART0.write((char)i++);  // ascii code for numbers A to Z
  myUART2.write((char)i++);  // ascii code for numbers A to Z
  
  //if (myUART0.available()) {
  if (myUART2.available()) {
    digitalWrite(LEDR, !digitalRead(LEDR));     // switch on / off
    do { // Read all to clear buffer
      //Serial.write(myUART0.read());    // Read it and send it out Serial (USB)
      Serial.write(myUART2.read());    // Read it and send it out Serial (USB)
    //} while (myUART0.available());
    } while (myUART2.available());
  }
  Serial.write("\n");    // Read it and send it out Serial (USB)
  delay(500); 
}

#endif


//////////////////// End All Core M7 Programing /////////////////////

//////////////////// Start All Core M4 Programing /////////////////////

#ifdef CORE_CM4 

int  myCount=48;  //48 = ascii 0,    58 ascii 9
char c;

//--assign Serial UART
//https://github.com/hpssjellis/portenta-pro-community-solutions <--- Most excellent URL
//Thank you, Jeremy Ellis!
//UART myUART1(PA_9,  PA_10, NC, NC); // put this back to test with with myUART0 on M7 Test1 - worked 20230218
UART myUART3(PJ_8,  PJ_9,  NC, NC); // put this back to test with with myUART2 on M7 Test2 - worked 20230218  

void setup() { 
  pinMode(LEDB, OUTPUT);   // LEDB = blue, LEDG or LED_BUILTIN = green, LEDR = red 
  // Serial.begin(115200);  // no serial monitor on M4 core without RPC

  //Most excellent URL ---> https://github.com/hpssjellis/portenta-pro-community-solutions
  //myUART1.begin(1000000);   
  //myUART1.setTimeout(10);
  myUART3.begin(1000000);   
  myUART3.setTimeout(10);
}

void loop() {

  if (myCount >= 58){myCount = 48;}             // ascii 48 =  number 0,   ascii 58 = number 9
  char x = (char)myCount++;
  //myUART1.write(x); 
  //myUART1.write(c); 
  myUART3.write(x); 
  myUART3.write(c); 

  //if (myUART1.available()) {
  if (myUART3.available()) {
    digitalWrite(LEDB, !digitalRead(LEDB));     // switch on / off
    do { // Read all to clear buffer
      //c = myUART1.read(); // c
      c = myUART3.read(); // c
    //} while (myUART1.available());
    } while (myUART3.available());
  }

  delay(500); 
}

#endif

//////////////////// End All Core M4 Programing /////////////////////