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diff --git a/Documentation/video4linux/zr36120.txt b/Documentation/video4linux/zr36120.txt new file mode 100644 index 0000000..4af6c52 --- /dev/null +++ b/Documentation/video4linux/zr36120.txt @@ -0,0 +1,159 @@ +Driver for Trust Computer Products Framegrabber, version 0.6.1 +------ --- ----- -------- -------- ------------ ------- - - - + +- ZORAN ------------------------------------------------------ + Author: Pauline Middelink <middelin@polyware.nl> + Date: 18 September 1999 +Version: 0.6.1 + +- Description ------------------------------------------------ + +Video4Linux compatible driver for an unknown brand framegrabber +(Sold in the Netherlands by TRUST Computer Products) and various +other zoran zr36120 based framegrabbers. + +The card contains a ZR36120 Multimedia PCI Interface and a Philips +SAA7110 Onechip Frontend videodecoder. There is also an DSP of +which I have forgotten the number, since i will never get that thing +to work without specs from the vendor itself. + +The SAA711x are capable of processing 6 different video inputs, +CVBS1..6 and Y1+C1, Y2+C2, Y3+C3. All in 50/60Hz, NTSC, PAL or +SECAM and delivering a YUV datastream. On my card the input +'CVBS-0' corresponds to channel CVBS2 and 'S-Video' to Y2+C2. + +I have some reports of other cards working with the mentioned +chip sets. For a list of other working cards please have a look +at the cards named in the tvcards struct in the beginning of +zr36120.c + +After some testing, I discovered that the carddesigner messed up +on the I2C interface. The Zoran chip includes 2 lines SDA and SCL +which (s)he connected reversely. So we have to clock on the SDA +and r/w data on the SCL pin. Life is fun... Each cardtype now has +a bit which signifies if you have a card with the same deficiency. + +Oh, for the completeness of this story I must mention that my +card delivers the VSYNC pulse of the SAA chip to GIRQ1, not +GIRQ0 as some other cards have. This is also incorporated in +the driver be clearing/setting the 'useirq1' bit in the tvcard +description. + +Another problems of continuous capturing data with a Zoran chip +is something nasty inside the chip. It effectively halves the +fps we ought to get... Here is the scenario: capturing frames +to memory is done in the so-called snapshot mode. In this mode +the Zoran stops after capturing a frame worth of data and wait +till the application set GRAB bit to indicate readiness for the +next frame. After detecting a set bit, the chip neatly waits +till the start of a frame, captures it and it goes back to off. +Smart ppl will notice the problem here. Its the waiting on the +_next_ frame each time we set the GRAB bit... Oh well, 12,5 fps +is still plenty fast for me. +-- update 28/7/1999 -- +Don't believe a word I just said... Proof is the output +of `streamer -t 300 -r 25 -f avi15 -o /dev/null` + ++--+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- 25/25 + +-s+-+-+-+-+-+-+-+-+-+-+-+-+-s+-+-+-+-+-+-+-+-+-+-+- + syncer: done + writer: done +(note the /dev/null is prudent here, my system is not able to + grab /and/ write 25 fps to a file... gifts welcome :) ) +The technical reasoning follows: The zoran completed the last +frame, the VSYNC goes low, and GRAB is cleared. The interrupt +routine starts to work since its VSYNC driven, and again +activates the GRAB bit. A few ms later the VSYNC (re-)rises and +the zoran starts to work on a new and freshly broadcasted frame.... + +For pointers I used the specs of both chips. Below are the URLs: + http://www.zoran.com/ftp/download/devices/pci/ZR36120/36120data.pdf + http://www-us.semiconductor.philips.com/acrobat/datasheets/SAA_7110_A_1.pdf + +The documentation has very little on absolute numbers or timings +needed for the various modes/resolutions, but there are other +programs you can borrow those from. + +------ Install -------------------------------------------- +Read the file called TODO. Note its long list of limitations. + +Build a kernel with VIDEO4LINUX enabled. Activate the +BT848 driver; we need this because we have need for the +other modules (i2c and videodev) it enables. + +To install this software, extract it into a suitable directory. +Examine the makefile and change anything you don't like. Type "make". + +After making the modules check if you have the much needed +/dev/video devices. If not, execute the following 4 lines: + mknod /dev/video c 81 0 + mknod /dev/video1 c 81 1 + mknod /dev/video2 c 81 2 + mknod /dev/video3 c 81 3 + mknod /dev/video4 c 81 4 + +After making/checking the devices do: + modprobe i2c + modprobe videodev + modprobe saa7110 (optional) + modprobe saa7111 (optional) + modprobe tuner (optional) + insmod zoran cardtype=<n> + +<n> is the cardtype of the card you have. The cardnumber can +be found in the source of zr36120. Look for tvcards. If your +card is not there, please try if any other card gives some +response, and mail me if you got a working tvcard addition. + +PS. <TVCard editors behold!) + Dont forget to set video_input to the number of inputs + you defined in the video_mux part of the tvcard definition. + Its a common error to add a channel but not incrementing + video_input and getting angry with me/v4l/linux/linus :( + +You are now ready to test the framegrabber with your favorite +video4linux compatible tool + +------ Application ---------------------------------------- + +This device works with all Video4Linux compatible applications, +given the limitations in the TODO file. + +------ API ------------------------------------------------ + +This uses the V4L interface as of kernel release 2.1.116, and in +fact has not been tested on any lower version. There are a couple +of minor differences due to the fact that the amount of data returned +with each frame varies, and no doubt there are discrepancies due to my +misunderstanding of the API. I intend to convert this driver to the +new V4L2 API when it has stabilized more. + +------ Current state -------------------------------------- + +The driver is capable of overlaying a video image in screen, and +even capable of grabbing frames. It uses the BIGPHYSAREA patch +to allocate lots of large memory blocks when tis patch is +found in the kernel, but it doesn't need it. +The consequence is that, when loading the driver as a module, +the module may tell you it's out of memory, but 'free' says +otherwise. The reason is simple; the modules wants its memory +contiguous, not fragmented, and after a long uptime there +probably isn't a fragment of memory large enough... + +The driver uses a double buffering scheme, which should really +be an n-way buffer, depending on the size of allocated framebuffer +and the requested grab-size/format. +This current version also fixes a dead-lock situation during irq +time, which really, really froze my system... :) + +Good luck. + Pauline |
