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 Format
MSB...........................................LSB
Word A
|0| NF | N1
|N2 or N2 and N2+N3|
|3 bits| 12 bits |
8 bits
|
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
N2 = 4 bits and N2+N3= 4 bits(modulo-16 addition).
Therefore if the following values are required NF=3
N1=51 N2=25 the input word would be
0
110
NF
110011000000
N1
10011000
N2
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).
SM1 SM2
0
0
0
1
1
0
1
1
RMAIN
M
2M
4M
8M
SA1,SA2 = Auxiliary reference source select (Raux).
SA1 SA2
0
0
0
1
1
0
1
1
RAUX
M
2M
4M
8M
FMOD = Fractional-N modulus select (5 or 8).
FMOD MODULUS
0
5
1
8
DA = Disable auxiliary synthesiser.
DA=1-disabled
DA=0-enabled
DM = Disable main synthesiser.
DM=1-disabled
DM=0-enabled
LONG = Word A or A2 select.
LONG=0 Word A selected
LONG=1 Word A2 selected
Word A2
|0| NF | N1
|N2 or N2 and N2+N3 | CN |
|3 bits | 12 bits |
8 bits
|8 bits |
CN = Scaling factor for current setting. (MSB first)
Word B
|1000 |N2+N3+N4| CN | K | L | P1,P2 |
| 4 bits | 8 bits|4 bits|2 bits| 2 bits |
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)
P1,P2 = Number of modulii of prescaler.
No. of modulii P2 P1
Two
0 0
Three
0 1
Four
1 0
Word C
|1001| NA |
|
| 12 bits | 8 bits free |
NA = Variable frequency for auxiliary synthesiser.
(MSB first)
8
MITEL [ MITEL NETWORKS CORPORATION ]
