Vizio VP50HDTV10A, Service Manual

Page: 41 / 102

CONFIDENTIAL – DO NOT COPY Page 7- 8
File No. SG-0219
Clock Generation
The FLI8125 accepts the following input sources:
1.Crystal Input Clock (TCLK and XTAL). This is the input pair to an internal crystal oscillator
and corresponding logic. Alternatively, a single ended TTL/CMOS clock input can be driven
into the XTAL pin (leave TCLK as n/c in this case).
2.External Clocks on various GPIOs for test purposes
3.Host Interface Transfer Clock (SCL), I2C slave SCL for DDC2Bi and another SCL for Serial
Inter-Processor Communication (SIPC)
4.Video Port VCLK
5.Second Video port clock. This is shared with ROM Address line 11. This is available only
when parallel ROM interface is not used.
Clock Synthesis
Additional synthesized clocks using PLLs:
1.Main Timing Clock (T_CLK) is the output of the chip internal crystal oscillator. T_CLK is
derived from the TCLK/XTAL pad input.
2.Reference Clock (R_CLK) synthesized by RCLK PLL using T_CLK or EXTCLK as the
reference.
3.Input Source Clock (SCLK) synthesized by SDDS PLL using input HS as the reference. In
case of analog composite video input this runs in open loop. The SDDS also uses the
R_CLK to drive internal digital logic.
4.Display Clock (DCLK) synthesized by DDDS PLL using IP_CLK as the reference. The
DDDS also uses the R_CLK to drive internal digital logic.
5.Fixed Frequency Clock (FCLK) synthesized by FDDS. Used as OCM_CLK domain driver.
6.Extended Clock (ECLK) synthesized by EDDS. Used by the decoder.
7.A fixed frequency clock created by LDDS (LCLK). Used by the expander in case of
panoramic scaling.