SAA7806H NXP [NXP Semiconductors], SAA7806H Datasheet - Page 29

• Manufacturer Part Number: SAA7806H
• Description: One chip automotive CD audio device
• Manufacturer: NXP [NXP Semiconductors]

Philips Semiconductors
9397 750 13697
Objective data sheet
6.6.5.3 Limiting the PLL frequency range
Influencing PLL behavior:
mainly for debugging purposes, and also to make difficult applications possible. The PLL
operation can be influenced in two ways. First, it is possible to hand-select the state the
PLL is in (in-lock, inner lock, outer lock, outer lock with only RL3 regulation). Second, it is
possible to pre-set the PLL frequency to a certain value.
Overruling the PLL’s state:
PLL state can be:
Normally, selection is done automatically using the lock detectors. Selection can be
overruled via register PLLLockAidControl. When LOCKMODE is left to ‘0’, user can still
select lockstate, but hardware will overwrite this if hardware selected lockstate means
closer to lock.
Table 5:
Remark: During PLL hold’ the frequency will not change and the frequency pre-set may
be used.
Writing the PLL frequency:
This is done by writing the integrator value of the PLL in register PLLIntegrator. The
relationship between the bit frequency, the integrator value, and the sysclk frequency is
given by:
The real-time value of the PLL frequency can be read on the same address.
The range over which the PLL can capture the input frequency can be limited. The
minimum and maximum PLL frequencies are set in bits MININTFREQ respectively
MAXINTFREQ of register PLLMinMaxBounds.
LOCKMODE
0
1
1
1
1
1
x
•
•
•
•
•
In-lock
Inner lock
Outer lock
Outer lock with RL3 regulation only
Hold.
f
PLL states
channelbit
=
PLLFreq 7:0
--------------------------------------------- -
Rev. 01 — 20 June 2005
Programmability and observerability is built into the PLL
It is possible to preset the PLL frequency to a certain value.
128
PLLLockControl
00000
00001
00110
00100
01000
10100
others
+
4
f
sysclk
One chip automotive CD audio device
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Meaning
automatic lock behavior
force HF PLL into in-lock
force HF PLL into inner lock aid
force HF PLL into outer lock aid
force HF PLL into hold mode
force HF PLL into outer lock aid
with RL3 regulation only
reserved
SAA7806
29 of 73