tm1300 NXP Semiconductors, tm1300 Datasheet - Page 129

• Manufacturer Part Number: tm1300
• Description: Tm-1300 Media Processor
• Manufacturer: NXP Semiconductors

Philips Semiconductors
2. Choose a value for PLL_S and PLL_T. For 8-40 MHz
3. Choose a value for CLOCK_SELECT. For 8-81 MHz
4. Assign values to the VO_CTL register containing the
Once the PLL is locked, small changes to the DDS fre-
quency are allowed, and the VO_CLK output will
smoothly track the frequency change.
Table 7-11. DDS and PLL example settings
4 – 10 MHz
8 – 45 MHz
40 – 81 MHz
Frequency
operation, a value of 1 (which selects division by 2) is
recommended.
operation, CLOCK_SELECT = 00 is recommended.
above choices. The first assignment with
CLOCK_SELECT not equal to 0x3 enables the PLL
system. Allow for a maximum of 50 microseconds to
achieve lock.
Desired
8 – 20 MHz
8 – 45 MHz
20 – 40.5 MHz
DDS frequency
1 (divide by 2)
1 (divide by 2)
1 (divide by 2)
PLL_S
1 (divide by 2)
1 (divide by 2)
3 (divide by 4)
PLL_T
Note: Most consumer electronics equipment imposes
very high precision requirements on the value of the col-
or burst frequency. A video encoder will derive the color
burst frequency from VO_CLK. When changing the
VO_CLK frequency in software to phase-lock the EVO to
a master reference, special care is required to keep the
color burst signal frequency within a tolerance of about
50 ppm. When using a Philips DENC (Digital Encoder),
the color burst frequency is derived from the master
DENC frequency by a programmable synthesizer on the
DENC chip. In this case, VO_CLK changes larger than
50 ppm are allowed by changing the DENC synthesizer
over its I
change.
Table 7-11
PRODUCT SPECIFICATION
01 (T divider)
00 (VCO)
00 (VCO)
CLOCK_SELECT
2
C interface to compensate for the VO_CLK
illustrates recommended settings.
Custom low speed video
Standard or 16:9 digital video
High pixel rate custom video
Enhanced Video Out
Usage
7-25