1.5. Dual-Port RAM Interface
n
0= divide by 1,
n
1= divide by 10,
n
2= divide by 100,
n
3= divide by 1000,
n
4= divide by 10000,
n
5= divide by 100000,
n
6= divide by 1000000,
n
7= divide by 10000000
n
F = divide by value in Period Register (when selected, refer to command 49)
Command 0x46: DDS Divide Source
The frequency synthesizer's divide chain has 3 possible input sources.
Byte
Type
Item
Value or Range
0
UINT8
ID
0x46
1
UINT8
Div sel
see below
n
0 =DDS
n
1 =Multiplier (DDS x multiplier)
n
2 =100 MHz (100 MHz PLL)
Command 0x47: DDS Synchronization Mode Select
The DDS frequency synthesizer's divider has 2 modes of operation, Fractional and Continuous. Frac-
tional mode allows for fractional frequencies to be generated that are time synchronized only when a
change is made to the DDS frequency but never again, allowing for non-integer rates. Continuous
mode should be used for integer rates only where the frequency synthesizer and divider are syn-
chronized each second. Note that integer frequency rates may use the fractional mode and it will
remain on time if the unit does not adjust phase using a jamsync. Note that this selection is restored
at power-up from NV memory.
Byte
Type
Item
Value or Range
0
UINT8
ID
0x47
1
UINT8
sync sel
see below
l
0 = Fractional (synchronizes only once - allows fractional rates)
l
1 = Continuous (synchronizes every second - integer frequencies)
- 55 -
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
