I have an issue with an ADV7181C where the crystal will not ocsillate. The conditions are listed below:
IC is powered (1.8V and 3.3V)
Reset pin is high
Powerdown pin is high
INT pin is not connected
The script below has been loaded via I2C. Locations 05,06 and 1D have been read back to confirm that they contain the correct values.
:625i/50Hz YPrPb In 8Bit 422 EAV/SAV out Encoder:
42 05 00 ; Prim_Mode =000b for SD-M
42 06 0B ; VID_STD=1010b for SD 4x1 525i
42 1D 47 ; Enable 28MHz Crystal
42 3A 11 ; Set Latch Clock 01b, Power Down ADC3
42 3B 81 ; Enable internal Bias
42 3C 52 ; PLL_QPUMP to 010b
42 67 13 ; DPP Filters
42 6B C3 ; Select 422 8 bit YPrPb out from CP
42 7B 06 ; clears the bits CP_DUP_AV and AV_Blank_EN
42 85 19 ; Turn off SSPD and force SOY. For Eval Board.
42 86 1B ; Enable stdi_line_count_mode
42 8A B0 ; Manual VCO_RANGE=01
42 8F 77 ; FR_LL to 1820 & Enable 28.63MHz LLC
42 90 1C ; FR_LL to 1820
42 BF 06 ; Blue Screen Free Run Colour
42 C0 40 ; default color
42 C1 F0 ; default color
42 C2 80 ; Default color
42 C5 01 ; CP_CLAMP_AVG_FACTOR[1-0] = 00b
42 C9 0C ; Enable DDR Mode
42 F3 07 ; Enable Anti Alias Filters on ADC 0,1,2
42 0E 80 ; ADI Recommended Setting
42 52 46 ; ADI Recommended Setting
42 54 00 ; ADI Recommended Setting
42 F6 3B ; ADI Recommended Setting
42 0E 00 ; ADI Recommended Setting
XTAL and XTAL1 have been measured with an oscilloscope and both seem to have just under 1V DC on them.
The crystal circuit itself is set up as per the manual (47pF caps and 1M resistor)
Trace lengths from the crystal to the pads are approx 10mm, run parallel to one another and are spaced approx 1mm apart.
Thanks in advance.