[ARM] RS485 with ST Nucleo F401RE, not sand data

[jocker]

hi to all

I'm trying to communicate with the energy meter (MODBUS protocol) using st nucelo F401RE via MAXIM MAX485 chip. I'm unable to receive any data from the energy meter. I can confirm that all my hardware is working correctly as i have extra for each component.I'm not sure if is the connection or the program's problem. I using Arduino uno rev.3 for try it. I use a oscilloscope but i don't see nothing, i think the problem is the serial comunication, can you help me?

this in my code:

#include "mbed.h"
#include "TextLCD.h"
 
Serial RS485(D1,D0); // Tx, Rx
DigitalOut ho(D2); // use this pin for able the RS485 trasmission
TextLCD lcd(D12, D11, D9, D8, D7, D6); // rs, e, d4-d7  --
int regvalue[9];
 
int main() {
     lcd.printf("START\n");    
  RS485.baud(9600);
    while(1) {
 
        ho = 1;                  // hight output from digital out pin
        RS485.putc(0x05);   // slave add
        RS485.putc(0x03);   // function code
        RS485.putc(0x00);   // Hi PDU add
        RS485.putc(0x13);   // low PDU add
        RS485.putc(0x00);   // Hi N reg 
        RS485.putc(0x02);   // Lo N reg
        RS485.putc(0x34);   // Hi CRC
        RS485.putc(0x4A);   // Lo CRC
        wait_ms(200);         // Silent interval
        ho = 0;                  // low output from digital out pin
        for (int count = 0; count < 8; count++) {
            regvalue[count] = RS485.getc(); // Retrieving received register from modbus
         lcd.printf(regvalue[count]);
        }
    lcd.printf("OK\n");     
        wait_ms(1000); 
   
 }
   
}