Help me with code for establishing communication between ADE7753 and STM32

[NanJ1007]

Hi,
I am doing a project using ade7753 and stm32.
I have some problem with Ade7753.
Can someone please help me.

1.
I have read the VRMS and IRMS.
For example,when the circuit have no load,the VRMS is 0x00002d3f,
I don't understand,the circuit have no load why the VRMS is not empty?
At result the calibration is not correct,VRMS error value is 400mv

2.
Every ade7753 need calibration?


This is my code,

AD_CS_L();
SPI2_ReadWrite(0x09|0x80);
Delay(1);
SPI2_ReadWrite(0x00);
Delay(1);
SPI2_ReadWrite(0x40);
Delay(1);
AD_CS_H();
Delay(60000);


AD_CS_L();
SPI2_ReadWrite(0x09|0x80);
Delay(1);
SPI2_ReadWrite(0x00);
Delay(1);
SPI2_ReadWrite(0X88);//
Delay(1);
AD_CS_H();
Delay(18);

AD_CS_L();
Delay(1);
SPI2_ReadWrite(REG_VRMSOS|0x80);
Delay(1);
SPI2_ReadWrite(0x19);
Delay(1);
SPI2_ReadWrite(0x29);
AD_CS_H();
Delay(2);

ADE7753_WR(REG_GAIN,0x0,1);
while(1)
{
ADE7753_RD(0x16,3);
ADE7753_RD(0x17,3);
}