AnsweredAssumed Answered

PLL, HMC830 are in use. The frequency does not match.

Question asked by EthanPark on Jul 4, 2018
Latest reply on Jul 5, 2018 by dyoung1

I am using the HMC830 Evolution board.
It is directly controlled by microcomputer SPI communication.

 

The reference frequency is 80 MHz.(external reference)

1882.5 MHz frequency works correctly.

However, the frequency of 1883.5 1884.5 1885.5 MHZ has a deviation of about + - 30~60HZ.

 

(Operation example

-1882.5 MHz / 80 MHz =  23.53125  

23 -> reg 03h(Integer Part)

0.53125 * 16777216(2^24) = 8912896 -> reg 04(Fractional Part)

 

- 1883.5 MHz / 80 MHz = 23.54375

23 -> reg 03h(Integer Part)

0.54375 * 16777216(2^24) = 9122611.2 -> 9122611 -> reg 04(Fractional Part)

 

- 1884.5 MHz / 80 MHz = 23.55625

23 -> reg 03h(Integer Part)

0.55625 16777216(2^24) = 9332326.4 -> 9332326 -> reg 04(Fractional Part)

 

example end. )

 

 

Is there a way to solve it?

This is the default value shown below.

Could there be a mistake in register settings?

 

Register, DATA

0x0,0x00000020
0x1,0x00000002
0x2,0x00000001

0x5,0x00001628
0x5,0x000060A0
0x5,0x0000E090
0x5,0x00002818
0x5,0x00000000

0x6,0x00030F4A  
0x7,0x0000014D 
0x8,0x00C1BEFF
0x9,0x005CBFFF
0xA,0x00002046
0xB,0x0007C061
0xC,0x00000000
0xF,0x00000081

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