Error: Identifier "I2CSlave" is undefined in MAX32630FTHR

Hi, I’m about to connect raspberry pi 4 as master and MAX32630FTHR as slave with I2C.
However, in MAX32630FTHR, it was outputted the message ; “Error: Identifier “I2CSlave” is undefined in “main.cpp”, Line: 14, Col: 2”.
I wrote definitely “#include “mbed.h””.
The photograph below is the error message.

  • targets device : MAX32630FTHR (as slave)
  • version of Mbed OS : 5.11.5 (online compiler)

Do you know anything about it?


how you can see below, this feature is not enabled for this target for some reason. That mean "I2CSalve" is missing under tag "device_has".

You can try to add that via the mbed_app.json via

    "target_overrides": {
        "*": {
            "target.device_has_add": ["I2CSlave"]

but if it is not supported/ implemented, that will not help you.

BR, Jan

1 Like

Thank you very much for kind reply.
I tried to add the mbeda_app.json that your advice.

However, the same error occurs. Maybe it is unsupported by the online compiler I’m using?

I do not think that issue is in the context with the Online compiler.
A piece of code, what connect Mbed I2CSlave API with Maxim’s HAL drivers, is probably missing from Maxim’s side.

BR, Jan

Could it be that I have no choice but to give up…?

  • You can try to make your own implementation with HAL drivers, maybe somewhere exist an example.
  • Switch to another board
  • See if Arduino has support for your board and I2C slave

BR, Jan

Thank you very much for kind reply, BR, Jan.

I have tried to do based on your advice as slave as Arduino Nano Every and master as MAX32630FTHR. It’s i2c ommunication properly . However, Communication exceeding 128 bytes happened character corruption.
Below are the errors at that time. (Screen Commands)

I want to communicate beyond 128 bytes, is there a better way?

main.cpp (MAX32630FTHR)

#include "mbed.h"
#include "max32630fthr.h"
#include <stdio.h>

#define SDA P5_7
#define SCL P6_0

MAX32630FTHR pegasus(MAX32630FTHR::VIO_3V3);
I2C i2c(SDA, SCL);

int main()
    int ArduinoAddress7bit = 0x08; //arduinoIDE内のarudinoのアドレス
    int ArduinoAddress8bit = ArduinoAddress7bit << 1; // ArduinoAddress7bit * 2 mbed内のarduinoのアドレス
    printf("ArduinoAddress8bit : %d\r\n", ArduinoAddress8bit); // 0x08なら16
    int val;
    int key;

    printf("I2CProgramm Start\r\n");
    char buff[256];
    while(1) {
        key = getchar();
        printf("input key:%c\r\n", key);,buff,sizeof(buff));  
        //printf("%d, ",buff[0]);
        //printf("%d \r\n",buff[1]);
        printf("%d \r\n", sizeof(buff));
        printf("%s \r\n", buff);

I2C_Slave.ino (Arduino Nano Every)

//SDA = A4
//SCL = A5
#include <Arduino.h>
#include <Wire.h>
#define THIS_ADDRESS 0x08
static byte sendmsg[] = "{'id': '01', 'class': 'human_front', 'avg_num': 2.2, 'date': '1605364660851.57', 'temperature_min': 14.87, 'temperature_max': 32.42}";
static int sendmsgsize = 0;

void setup() {
  pinMode(A4, INPUT); // disable pullup
  pinMode(A5, INPUT); // disable pullup
  Serial.println("STARTUP -- OK!");

void loop() {
  // delay(1000);

void requestEvent() {
  sendmsgsize = sizeof(sendmsg);
  Serial.print("sendmsgsize : ");
  for(int i = 0; i < sizeof(sendmsg); i++){