// printf("modbus_rtu_set_serial_mode: %d \n",rc1); res = modbus_rtu_set_rts(ctxRTU, MODBUS_RTU_RTS_UP); printf("modbus_rtu_set_rts: %d \n",res); // modbus_rtu_set_rts_delay(ctxRTU,1000); res=modbus_rtu_set_custom_rts(ctxRTU, csetrts()); //GPIO20 printf("modbus_rtu...