Si5345-44-42-D-RM
158
Rev. 1.0
Si5344
This bit is provided so that all of the divider bits can be changed at the same time. First, write all of the new values
to the divider, then set the update bit.
Bit 0 corresponds to MultiSynth N0 N_FSTEP_MSK 0x0339[0]
Bit 1 corresponds to MultiSynth N1 N_FSTEP_MSK 0x0339[1]
Bit 2 corresponds to MultiSynth N2 N_FSTEP_MSK 0x0339[2]
Bit 3 corresponds to MultiSynth N3 N_FSTEP_MSK 0x0339[3]
This is a 44-bit integer value which is directly added or subtracted from the N-divider. When FINC or FDEC is set to
a 1, ClockBuilder Pro calculates the correct values for the N0 Frequency Step Word. Each N divider has the ability
to add or subtract up to a 44-bit value.
Register 0x0338 Global N Divider Update
Reg Address
Bit Field
Type
Name
Description
0x0338
1
R/W
N_UPDATE
Set this bit to update all five N dividers.
Register 0x0339 FINC/FDEC Masks
Reg Address
Bit Field
Type
Name
Description
0x0339
3:0
R/W
N_FSTEP_MSK
0 to enable FINC/FDEC updates
1 to disable FINC/FDEC updates
Register 0x033B-0x0340 N0 Frequency Step Word
Reg Address
Bit Field
Type
Name
Description
0x033B
7:0
R/W
N0_FSTEPW
44-bit Integer Number
0x033C
15:8
R/W
N0_FSTEPW
0x033D
23:16
R/W
N0_FSTEPW
0x033E
31:24
R/W
N0_ FSTEPW
0x033F
39:32
R/W
N0_ FSTEPW
0x0340
43:40
R/W
N0_ FSTEPW
Table 55. Registers that Follow the N0_FSTEPW Definition
Register Address
Description
Size
Same as Address
0x0341-0x0346
N1 Frequency Step Word
44-bit Integer Number
0x033B-0x0340
0x0347-0x034C
N2 Frequency Step Word
44-bit Integer Number
0x033B-0x0340
0x034D-0x0352
N3 Frequency Step Word
44-bit Integer Number
0x033B-0x0340