I have a need to build a 3910 MHz PLL. I decided to use a Mini circuit integrated PLL/VCO part number KSN-3940. It's a great device and the base PLL uses the ADF4106.
As I need to set the frequency only once at power up and not having much experience on programming Micros, the PICAXE 20x2 when configured using hspisetup made sense and it keeps the design simple from my point of view.
Unfortunately, I am struggling to obtain a frequency anywhere near 3910 MHz using basic register values and a 20MHz ref in and a 10MHz PD
F = 0x5F8092
R = 8
N = 1819
During power cycles, I can obtain a mix out digital lock for ~2940MHz, however it's all over the place and obviously a false lock.
I have reviewed the Latch, clock and data alignment on a digital CRO, they appear to be fine and closely match the data sheet timing diagram.
After 2 days of experimenting, I am at a total loss and struggle to find any answer.
The code I am working on goes like this
symbol LE = c.0
'==== F-Register =========
hspiout (%01011111,%10000000,%10010010) '24bits
'===== N-Register ========
hspiout (%00000000,%00011000,%00101001) '24 bits
'====== R-Register ========
hspiout (%00000000,%00000000,%00001000) '24bits
Standard pins used on the 20x2 are
Pin 9 SPI data out
Pin 10 LE
Pin 11 SPI CLK
I know this isn't an answer AD could possibly give, I hope another user may have greater experience with ADF4106 and Picaxe.