Information for linux-fslc (4.x) driver for Freescale iMX233 TVENC.

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Information for linux-fslc (4.x) driver for Freescale iMX233 TVENC.

Contributor I

I am using the Freescale iMX233 on custom hardware and trying to get the TV Encoder to work.

I would like to connect the composite video output to my (NTSC) TV screen.

I have used the Linux 2.6. as a reference and followed the example in the iMX233 Data Sheet from freescale.

I currently am using Linux-fslc 4.0.7. , but I am setting up the TVENC Registers in u-boot-fslc 2015.04-001310g5d9ffd2, and checking to see they are set correctly, once the DMA is running in Linux-fslc 4.0.7.

I am reading back the TVENC, LCDIF and CLK Registers to ensure the setting are that described by the examples are correct.

I have a frame buffer set up, but I am only copying a still picture into it (logo).

my frame buffer setting are as follows:

/ # fbset

mode "640x480-64"

        # D: 27.000 MHz, H: 33.750 kHz, V: 64.286 Hz

        geometry 640 480 640 480 16

        timings 37037 40 24 32 11 96 2

        accel false

        rgba 5/11,6/5,5/0,0/0


maybe something is wrong here ?

I have tried the internal color bar generator in case the frame buffer is in error.

No change.

I have read the iMX233 data sheet and checked the signals at the LCD pins with an oscilloscope. The data sheet only speaks about the RS pin should have 27 MHz on it. I see the following:

The RS pin is toggling at 27 MHz.

The Data Bus pin D4 is toggling at 13.1 MHz.

The Data Bus pin D7 is toggling at 13.1 MHz.

The Data Bus pins D0-D3 and D5-D6 have short random pulses.

D8 - D15 are low level.

I read through Chapter 48 in the iMX233 DataSheet on how the Sarnoff Digital Video Encoder works.

There are a few hints, about 13.5 MHz and 6.75 MHz signals. I think these are internal and do not have anything to do with the 13.1 MHz signal I see at the LCD Data Bus.

I currently have a 75 OHM Resistor and 5- pf capacitor terminating the VDAC Output and when everything is running I have a  0.7 Volt DC offset output, but have no video and no sync signals.

I would expect to see some sync signal or something other than just the DC offset.

Would you kindly please step me though the process. If any one has a patch for the linux-fslc 4.0.7, or would just point me to more information, as a google search does not give any usable info.

Also if anyone has used the following LCD panel (FPC3507-12) would you Please let me know where I can find more information, as google does not supply me with any info.

Thanking you very Kindly

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NXP Employee
NXP Employee

Maybe you could post your current patch as RFC (Request for Comments) in the linux-media mailing list? Then people can review it and try to come up with ideas as to why tvenc is not functional.

If you follow this route, then please generate the patch against 4.4-rc1.


Fabio Estevam

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