Si5345-44-42-D-RM
Si5345
Rev. 1.0
87
Figure 54 shows the logic for the FINC, FDEC bits.
Figure 54. FINC, FDEC Logic Diagram
Register 0x001D FINC, FDEC
Reg Address
Bit Field
Type
Name
Description
0x001D
0
S
FINC
1 a rising edge will cause the selected MultiSynth to incre-
ment the output frequency by the Nx_FSTEPW parameter.
See registers 0x0339–0x0358
0x001D
1
S
FDEC
1 a rising edge will cause the selected MultiSynth to decre-
ment the output frequency by the Nx_FSTEPW parameter.
See registers 0x0339–0x0358
Register 0x001E Sync, Power Down and Hard Reset
Reg Address
Bit Field
Type
Name
Description
0x001E
0
R/W
PDN
1 to put the device into low power mode
0x001E
1
S
HARD_RST
1 causes hard reset. The same as power up except
that the serial port access is not held at reset. This
does not self-clear, so after setting the bit it must be
cleared.
0 No reset
0x001E
2
S
SYNC
Logically equivalent to asserting the SYNC pin.
Resets all R dividers to the same state.
Register 0x002B SPI 3 vs 4 Wire
Reg Address
Bit Field
Type
Name
Description
0x002B
3
R/W
SPI_3WIRE
0 for 4-wire SPI, 1 for 3-wire SPI
0x002B
5
R/W
AUTO_NDIV_UPDATE
FINC, 1Dh[0]
(self clear)
FDEC is the same as FINC
NxFINC
N_FSTEP_MSKx, 339h[4:0]
FINC pin,
pos edge trig