m21262 Mindspeed Technologies, m21262 Datasheet - Page 24

• Manufacturer Part Number: m21262
• Description: Cdr/reclocker With 4 1 Input Multiplexer
• Manufacturer: Mindspeed Technologies

frequency difference exceeds the larger window (WRW), LOL L-to-H occurs to signal an out of lock case. When
LOL = H (and LOA = L), the frequency difference is brought within the narrow reference window (NRW), after which
LOL makes a H-to-L transition signaling in-lock. If LOA = H when LOL = L, the FLL remains on to keep the VCO
locked to the reference, until a signal is present. N
LOL_ctrl [4:1], and N
making an LOL decision. This averaging time is referred to as the LOL decision time or DT
Table 1-14
and two-wire serial interface modes.
Table 1-14.
1.1.18
If the automatic rate detection (ARD) algorithm developed by Mindspeed is used, it is not necessary for the user to
manually program the registers of the reclockers to configure the reclockers for operation at a specific data rate. In
applications where the ARD is not implemented and the device is used with software control, there are a few
parameters that must be configured for the reclocker to correctly lock to the input data. The parameters that need
to be programmed are the data rate divider (DRD) and the VCO frequency divider (VCD). The DRD is programmed
using bits [3:0] of register address 41h. The VCD is programmed using bits [7:0] of register address 42h. The
following table shows the recommended values of DRD and VCD for standard video data rates.
Table 1-15.
21262-DSH-001-C
Hardwired mode default
Two-wire serial interface mode default
iFV = iFR
Fast lock
NOTES:
1.
2.
Decision time is calculated with iFR = 19.44 MHz; will scale proportionally with iFR range from 10 to 25 MHz.
Above are examples showing ability to tailor windows for data rates, reference frequencies, and acquisition times.
Data Rate (Mbps)
1483.5/1485
2967/2970
shows various window sizes for different applications, including the default value in both the hardwired
143
177
270
360
540
Condition
LOL Window Size and Decision Time Examples
Recommended Values of DRD and VCD for Standard Video Data Rates
CDR/Reclocker Data Rate Programming (HD/SD-SDI data rates only)
wide
is defined with LOL_ctrl [0]. The LOLCir averages a large number of transitions before
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DRD Value
N
101b
101b
111b
010b
acq
05h
04h
03h
03h
02h
01h
00h
N
0100b
0100b
0010b
0001b
narrow
acq
is defined with LOL_ctrl [7:5], N
N
wide
0b
0b
1b
0b
VCD Value
®
B1h
B4h
B4h
BFh
F0h
F7h
F7h
Window
Narrow
(ppm)
±1955
±1955
±5860
±245
narrow
Window
(ppm)
Wide
±2930
±2930
±7800
Functional Description
±975
LOL
is defined with
.
Fref (MHz)
12
12
12
12
12
12
12
Decision
Time
1685
(
420
420
µ
56
s)
16