How to set the VCO frequency?

Hello everyone, I have a custom board with Spartan 6 and LMS7002M

How do I set the VCO frequency?

I read document LMS7002M_Programming_and_Calibration_Guide_v31r05.pdf
It has C pseudo code for SXT / SXR VCO coarse tuning on page 101:

unsigned char VCO_CoarseTuning_SXT_SXR (float Fref_MHz, float Fvco_des_MHz, unsigned char ch)
{
unsigned short Nround;
unsigned char i, try_cnt;
MIMO_Ctrl (ch); // SXT SXR selection
// Initialization
Modify_SPI_Reg_bits (0x011C, 12, 12, 1); // 1) EN_COARSEPLL = 1, a. VCO control voltage is switched to a DC = VDD / 2
Modify_SPI_Reg_bits (0x0121, 0, 0, 0); // 2) COARSE_START = 0
Modify_SPI_Reg_bits (0x011C, 9, 9, 1); // 3) EN_INTONLY_SDM = 1
Modify_SPI_Reg_bits (0x011C, 14, 14, 1); // 4) SHORT_NOISEFIL = 1 SPDUP_VCO_ Short the noise filter resistor to speed up the settling time
Nround = (unsigned short) (4 * Fvco_des_MHz / Fref_MHz + 0.5); // 5) Nround = round (4 * Fvco_des / Fref)
Modify_SPI_Reg_bits (0x011D, 15, 0, 0); // 6) FRAC_SDM = 0
Modify_SPI_Reg_bits (0x011E, 3, 0, 0);
Modify_SPI_Reg_bits (0x011E, 13, 4, (Nround-4)); // 7) INT_SDM = Nround-4
Modify_SPI_Reg_bits (0x0121, 10, 3, 0); // 9) Set SWC_VCO <7: 0> = <00000000>
i = 7; // 10) i = 7
// Decision - Loop Section
while (1)
{
Modify_SPI_Reg_bits (0x0121, 3 + i, 3 ​​+ i, 1); // SWC_VCO = 1
Modify_SPI_Reg_bits (0x0121, 0, 0, 1); // COARSE_START = 1
while (Get_SPI_Reg_bits (0x0123, 15, 15)! = 1) // wait till COARSE_STEPDONE = 1
{
try_cnt ++;
if (try_cnt> MAX_TRY_CNT) return 0;
}
if (Get_SPI_Reg_bits (0x0123, 14, 14) == 1) // check CAORSEPLL_COMPO
{
Modify_SPI_Reg_bits (0x0121, 3 + i, 3 ​​+ i, 0); // SWC_VCO = 0
}
Modify_SPI_Reg_bits (0x0121, 0, 0, 0); // COARSE_START = 0
if (i == 0) break;
i–;
}
// Normal mode setting
Modify_SPI_Reg_bits (0x011C, 12, 12, 0); // EN_COARSEPLL = 0
Modify_SPI_Reg_bits (0x011C, 9, 9, 0); // EN_INTONLY_SDM = 0
Modify_SPI_Reg_bits (0x011C, 14, 14, 0); // SHORT_NOISEFIL = 0 SPDUP_VCO_ Short the noise filter resistor to speed up the settling time
return 1;
}

However, this code does not contain the VCO enable bit PD_VCO_ (SXR, SXT): Power down for VCO
0x011C register

When I turn on PD_VCO_SXT, I have a 949 MHz signal output, although I set it to 1000 MHz.

Please tell me the algorithm for setting the VCO frequency.
Please help me