Time Sync Registers
BCM5718 Programmer’s Guide
Broadcom
®
January 29, 2016 • 5718-PG108-R
Page 160
Time Sync Registers
GRC MODE REG [0x6800]
EAV REF COUNT CAPTURE LSB REG [Offset 0x6900]
The MSB and LSB registers are interface to the actual EAV Ref Counter hardware. The Counter value may be
read via this pair anytime and even be overwritten by this pair anytime. While reading the pair, the hardware
Counter does not stop, only its value is latched in this pair.
The only two legal sequences of accessing this pair is Read-LSB followed by Read-MSB and Write-LSB
followed by Write-MSB.
EAV REF COUNT CAPTURE MSB REG [Offset 0x6904]
Name
Bits
Access Default Value Description
Legacy
31:20
Time Sync Mode Enable 19
RW
0
Write 1 to this bit to enable Time Sync Mode.
Legacy
20:0
Name
Bits
Access Default Value Description
EAV Reference Count
[lower half]
31:3 RW
UUUU
LSB of the EAV Reference Count – Reading this LSB
latches a Count in this pair until the time the
corresponding MSB is read.
Writing to this LSB latches the value in this pair and
the subsequent write to the MSB transfers the 64-bit
value to EAV Ref Counter and counting immediately
resumes from there.
Reserved
2:0
RO
000
[2:0] shall always be 000.
Name
Bits
Access Default Value Description
EAV Reference Count
[Upper half]
31:0 RW
UUUU
MSB of the EAV Reference Count – See the pairing
LSB register.
Reading this register returns the MSB of the 64- bit
EAV Ref count previously latched by performing an
LSB read.
Writing to this MSB transfers the 64-bit value, this
plus previously latched LSB, to EAV Ref Counter and
counting immediately resumes from there.
Back to back writes to this MSB has no effect.