NJ88C50
The information contained within each word is given below.
Data bits are shifted in on the leading clock edge, with the least
significant bit(LSB) of the word first and the MSB of the word
last. (Note that individual sections of data within a word are
loaded with the MSB of that section first. An example of this
is given after this description of Word A)
Word D
|1010 | NR |SM1,SM2| DM |SA1,SA2| DA|FMOD|LONG|
|12 bits| 2 bits | 1 bit | 2 bits |1 bit| 1 bit | 1 bit |
NR = Reference frequency division value. (MSB first)
SM1,SM2 = Main reference source select (Rmain).
Word Format
MSB...........................................LSB
Word A
SM1 SM2 RMAIN
0
0
1
1
0
1
0
1
M
2M
4M
8M
|0| NF | N1
|N2 or N2 and N2+N3|
8 bits
|3 bits| 12 bits |
|
SA1,SA2 = Auxiliary reference source select (Raux).
NF = Fractional-N incremental value. (MSB first)
N1 = Number of cycles prescaler ratio R1 is used. (MSB first)
N2 = Number of cycles prescaler ratio R2 is used. (MSB first)
N3 = Number of cycles prescaler ratio R3 is used. (MSB first)
If a two modulus prescaler is being used N2= 8 bits.
If a three or four modulus prescaler is being used
SA1 SA2 RAUX
0
0
1
1
0
1
0
1
M
2M
4M
8M
N2 = 4 bits and N2+N3= 4 bits(modulo-16 addition).
FMOD = Fractional-N modulus select (5 or 8).
FMOD MODULUS
Therefore if the following values are required NF=3
N1=51 N2=25 the input word would be
0
1
5
8
0
110 110011000000 10011000
NF N1 N2
DA = Disable auxiliary synthesiser.
Word A2
|0| NF | N1
|3 bits | 12 bits |
|N2 or N2 and N2+N3 | CN |
8 bits |8 bits |
DA=1-disabled
DA=0-enabled
CN = Scaling factor for current setting. (MSB first)
DM = Disable main synthesiser.
Word B
|1000 |N2+N3+N4| CN | K | L | P1,P2 |
4 bits | 8 bits|4 bits|2 bits| 2 bits |
DM=1-disabled
DM=0-enabled
|
LONG = Word A or A2 select.
N4 = Number of cycles prescaler ratio R4 is used and
(N2+N3+N4) is modulo-16 addition. (MSB first)
CN = Scaling factor for current setting. (MSB first)
K = Acceleration factor for integral charge pump. (MSB first)
L = Acceleration factor for proportional charge pump.
(MSB first)
LONG=0 Word A selected
LONG=1 Word A2 selected
P1,P2 = Number of modulii of prescaler.
No. of modulii P2 P1
Two
Three
Four
0 0
0 1
1 0
Word C
|1001| NA
|
|
| 12 bits | 8 bits free |
NA = Variable frequency for auxiliary synthesiser.
(MSB first)
8
MITEL [ MITEL NETWORKS CORPORATION ]
