LMH1983 Datasheet, PDF (28/55 Pages) National Semiconductor (TI) – Generating 44.1 kHz Based highly integrated programmable audio

LMH1983
SNLS309I – APRIL 2010 – REVISED DECEMBER 2014
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Register Map (continued)
ADD NAME
0x11 Alignment Control – TOF1
0x12 Alignment Control – TOF2
0x13 Alignment Control – TOF3
Table 3. LMH1983 Register Map (continued)
BITS FIELD
7:6 RSVD
5:4 TOF1_Align_Mode
3:2 TOF1_Sync
1
TOF1_Sync_Slew
0
RSVD
7:6 RSVD
5:4 TOF2_Align_Mode
3:1 RSVD
0
TOF2_INIT
7:6 RSVD
5:4 TOF3_Align_Mode
3:1 RSVD
0
TOF3_INIT
R/W DEFAULT
DESCRIPTION
00
Reserved
00 = Auto-align when misaligned
R/W
11
01 = Reserved
10 = Always Align
11 = Never Align⁽¹⁾
This bit sets the PLL1/TOF1 output synchronization behavior
when the same reference is reapplied following a momentary
LOR condition and TOF1 is within 2 lines of the expected
location.
00 = Always Drift Lock – ensures the outputs drift smoothly
R/W
01
back to frame alignment without excessive output phase
disturbances
01 = Drift Lock if output < (2^LOA_window x 27 MHz Clock). Crash
Lock otherwise.
1X = Always Crash Lock – achieves the fastest frame
alignment through PLL/TOF counter resets, which can result in
output phase disturbances
Sets the direction that TOF1 slews to achieve frame alignment
when a new reference is applied and TOF1 is outside of 2
R/W
0
lines of the expected location.
0 = TOF1 lags by railing the VCXO input low
1 = TOF1 advances by railing the VCXO input high
0
Reserved
00
Reserved
00 = auto align when misaligned
R/W
11
01 = one shot manual align when writing TOF2_INIT=1
10 = always align
11 = never align
000
Reserved
Writing one to this bit while also writing TOF2_Align_Mode =
3, will cause the TOF2_INIT output to go high for at least one
vframe period + one Hsync period and not more than one
R/W
0
vframe period + two Hsync periods. The assertion of
TOF2_INIT must happen immediately (it cannot wait for
Hsync). If TOF2_Align_Mode is being written to 3, this bit will
have no effect. This bit is self-clearing and will always read
zero.
00
Reserved
00 = auto align when misaligned
R/W
11
01 = one shot manual align when writing TOF3_INIT=1
10 = always align
11= never align
000
Reserved
Writing one to this bit while also writing TOF3_Align_Mode ≠
3, will cause the TOF3_INIT output to go high for at least one
vframe period + one Hsync period and not more than one
R/W
0
vframe period + two Hsync periods. The assertion of
TOF3_init must happen immediately (it cannot wait for Hsync).
If TOF3_Align_Mode is being written to 3, this bit will have no
effect. This bit is self-clearing and will always read zero.
(1) NOTE: When H_ONLY is 1, TOF1 align mode is forced to never align.
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