LMX1204: questions about register bit

Kazuhiko Hirano

Part Number: LMX1204
Other Parts Discussed in Thread: LMX1906-SP

Tool/software:

Hello,

My customer has questions about register setting as follows.

Q1:
Datasheet page 30 says D9 and D8 of R15 are 1 and SYSREF_SP_EN respectively. However, datasheet page 43 says the D9 and the D8 are reserved and they should be always 0x1, is this mean “D9D8”=”11”?

Q2:
What is the SYSREF_SP_EN? Should it be always 1? Please let me know the definition and meaning of SYSREF_SP_EN.

Q3:
From functional point of view, LMX1204 R15 D7 “SYSREF_EN” is the same as LMX1906-SP R15 D8 “SYSREF_EN”? And, LMX1204 R8 D4 “LOGIC_EN” is the same as LMX1906-SP R8 D5 “LOGIC_EN”?

Best regards,

K.Hirano

9 months ago

0 Michael Srinivasan 9 months ago

TI__Genius 12420 points

Hi Hirano-san,

Kazuhiko Hirano said:
is this mean “D9D8”=”11

This is correct. In the TICS Pro register configuration, D9D8 is always 11.

Kazuhiko Hirano said:
What is the SYSREF_SP_EN? Should it be always 1? Please let me know the definition and meaning of SYSREF_SP_EN.

SYSREF_SP_EN enables SYSREF subsystem (and SYNC subsystem when SYSREFREQ_MODE = 0x0). Setting this bit to 0x0 completely disables all SYNC, SYSREF, and clock position capture circuitry, overriding the state of other powerdown/enable bits except SYNC_EN. If SYNC_EN = 0x1, the SYNC path and clock position capture circuitry are still enabled, regardless of the state of SYSREF_EN. This should always be set to 1.

Kazuhiko Hirano said:
From functional point of view, LMX1204 R15 D7 “SYSREF_EN” is the same as LMX1906-SP R15 D8 “SYSREF_EN”? And, LMX1204 R8 D4 “LOGIC_EN” is the same as LMX1906-SP R8 D5 “LOGIC_EN”?

That is correct.

Thanks,

Michael

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LMX1204: questions about register bit