HMC7044 Datasheet, PDF (61/72 Pages) Analog Devices – JESD204B clock generation

Data Sheet
HMC7044
SYSREF/SYNC Control (Register 0x005A to Register 0x005E)
Table 57. Pulse Generator Control
Address Bits Bit Name
0x005A [7:3] Reserved
[2:0] Pulse Generator
Mode
Selection[2:0]
Settings
000
001
010
011
100
101
110
111
Description
Reserved.
SYSREF output enable with pulse generator.
Level sensitive. When the GPIx is configured to issue a pulse generator
request (GPIx Selection[3:0] = 1000), or a pulse generator request is issued
through the SPI or as a SYNC pin-based pulse generator, run the pulse
generator. Otherwise, stop the pulse generator.
1 pulse.
2 pulses.
4 pulses.
8 pulses.
16 pulses.
16 pulses.
Continuous mode (50% duty cycle).
Access
RW
Table 58. SYNC Control
Address Bits Bit Name
0x005B [7:3] Reserved
2 SYNC retime
1 SYNC through PLL2
0 SYNC polarity
Settings
0
1
0
1
Description
Reserved
Bypass the retime (if using SYNC path with on-chip VCO)
Retime the external SYNC from Reference 0
Allow a reseed event to be through PLL2
SYNC polarity (must be 0 if not using CLKIN0/CLKIN0 as the input)
Positive
Negative
Access
RW
Table 59. SYSREF Timer Control
Address Bits Bit Name
0x005C
[7:0] SYSREF
Timer[7:0]
(LSB)
0x005D
[7:4] Reserved
[3:0] SYSREF
Timer[11:8]
(MSB)
Settings
Description
12-bit SYSREF timer setpoint LSB. This sets the internal beat frequency of the
master timer, which controls synchronization and pulse generator events. Set the
12-bit timer to a submultiple of the lowest output SYSREF frequency, and
program it to be no faster than 4 MHz.
Reserved.
12-bit SYSREF timer setpoint MSB.
Access
RW
RW
Table 60. SYSREF Miscellaneous Control
Address
Bits
Bit Name
0x005E
[7:0]
Reserved
Settings
Description
Reserved
Access
RW
Clock Distribution Network (Register 0x0064 to Register 0x0065)
Table 61. External VCO Control
Address Bits Bit Name
0x0064 [7:2] Reserved
1
Divide by 2 on external VCO enable
0
Low frequency external VCO path
Settings
Description
Reserved
Use divide by 2 on external VCO path
Changes bias to Class A for low frequency VCO
Access
RW
Rev. B | Page 61 of 72