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| cxadc-linux3 | ||
| ============ | ||
| # cxadc | ||
|
|
||
| CX2388x direct ADC capture driver, updated for Linux 3.11 | ||
| cxadc is an alternative Linux driver for the Conexant CX2388x video | ||
| capture chips used on many PCI TV cards. It configures the CX2388x to | ||
| capture raw samples from the input ports, allowing these cards to be | ||
| used as a low-cost 28Mhz ADC for SDR and similar applications. | ||
|
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| Notes for Linux 3.x version 0.2 (cxadc 0.4+) 18 Dec 2013 | ||
| ======================================================== | ||
| The regular cx88 driver in Linux provides support for capturing composite | ||
| video, digital video, audio and the other normal features of these | ||
| chips. You shouldn't load both drivers at the same time. | ||
|
|
||
| This version has been retargeted for ubuntu 13.10 Linux 3.11. | ||
| ## Getting started | ||
|
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||
| While still a mess, the driver has been simplified a bit. Data is now read | ||
| using standard read() semantics, so no capture program is needed like the original | ||
| version. | ||
|
|
||
| For the first time, it also runs on 64-bit Linux, and *seems* to be OK under | ||
| SMP. | ||
|
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||
| Caveats: | ||
|
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| - Still need to mknod | ||
| - Does not support runtime parameters yet | ||
|
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| - generally nowhere near linux coding standards | ||
|
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||
| - Chad Page | ||
| [email protected] | ||
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| /* | ||
| History | ||
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||
| 25 sep 2005 - added support for i2c, use i2c.c to tune | ||
| - set registers to lower gain | ||
| - set registers so that no signal is nearer to sample value 128 | ||
| - added vmux and audsel as parms during driver loading | ||
| (for 2nd IF hardware modification, load driver using vmux=2 ) | ||
| By default audsel=2 is to route tv tuner audio signal to | ||
| audio out of TV card, vmux=1 use the signal from video in of tv card | ||
|
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||
| Feb-Mac 2007 - change code to compile and run in kernel 2.6.18 | ||
| - clean up mess in version 0.2 code | ||
| - it still a mess in this code | ||
| */ | ||
| Build the out-of-tree module as usual: | ||
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| make -C /lib/modules/$(uname -r)/build M=$PWD modules | ||
|
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||
| ---- | ||
| Notes for cxadc.c and cxcap.c 24 Mac 2007 | ||
| ========================================== | ||
| Load the module, adjusting parameters as needed: | ||
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||
| The purpose of these program is to get continuous 8 bit ADC raw data from | ||
| the CX2388x based TV cards. TV tuner functions are not supported. Register to | ||
| initialized sampling rate is not used. By default, after reset, sampling rate is | ||
| 27 Mhz. | ||
| insmod cxadc.ko vmux=2 | ||
|
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||
| These program are developed on Fedora Core 6. (kernel 2.6.18) | ||
| Create the device: | ||
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| mknod /dev/cxadc c 126 0 | ||
|
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||
| cxadc.c is the driver for CX2388x TV card | ||
| cxcap.c is the program and get the raw data from the driver and store it into file. | ||
| Build the level adjustment tool: | ||
|
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||
| These codes are a bit messy since I have no time to clean up. It might contain bugs | ||
| but at least it runs (on my machine). | ||
| make leveladj | ||
|
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||
| Quick procedure to get it running (capture from video in of card) | ||
| ================================================================= | ||
| Connect a signal to the input you've selected, and run `leveladj` to | ||
| adjust the gain automatically: | ||
|
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||
| Instruction may be specific to PixelView PlayTV Pro Ultra TV card | ||
| ./leveladj | ||
|
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||
| WARNING : Before trying, make sure you have backup your important data | ||
| just in case. | ||
| Open `/dev/cxadc` and read samples. For example, to capture 10 seconds | ||
| of samples: | ||
|
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||
| a) copy cxadc.c and cxcap.c to a new folder on the hard disk (mounted r/w) | ||
| sox -r 28636363 -b 8 -c 1 -e unsigned -t raw /dev/cxadc capture.wav trim 0 10 | ||
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| b) run 'make' to compile cxadc.c | ||
| ## Module parameters | ||
|
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||
| c) to compile cxcap, type in | ||
| Most of these parameters (except `latency`) can be changed using sysfs | ||
| after the module has been loaded. Re-opening the device will update the | ||
| CX2388x's registers. | ||
|
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||
| gcc cxcap.c -o cxcap | ||
| ### `audsel` (0 to 3, default none) | ||
|
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| d) create device node with the following command. (make sure you are super user) | ||
| Some TV cards (e.g. the PixelView PlayTV Pro Ultra) have an external | ||
| multiplexer attached to the CX2388x's GPIO pins to select an audio | ||
| channel. If your card has one, you can select an input using this | ||
| parameter. | ||
|
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| mknod /dev/cxadc c 126 0 | ||
| On the PlayTV Pro Ultra: | ||
| - `audsel=0`: tuner tv audio out? | ||
| - `audsel=1`: silence? | ||
| - `audsel=2`: fm stereo tuner out? | ||
| - `audsel=3`: audio in to audio out | ||
|
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| e) install driver | ||
| ### `latency` (0 to 255, default 255) | ||
|
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| insmod ./cxadc.ko | ||
| The PCI latency timer value for the device. | ||
|
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||
| f) check 'dmesg' output to see whether it is similiar to the one | ||
| shown in the cxadc.c source code | ||
| ### `level` (0 to 31, default 16) | ||
|
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||
| g) If it is ok, run cxcap to capture 8Mbyte of raw data. The signal source is feed into the | ||
| video input of the CX2388x tv card. | ||
| The fixed digital gain to be applied by the CX2388x (`INT_VGA_VAL` in | ||
| the datasheet). Adjust to minimise clipping; `leveladj` will do this | ||
| for you automatically. | ||
|
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| ./cxcap | ||
| ### `tenbit` (0 or 1, default 0) | ||
|
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| h) Check 'dmesg' output to see the result similiar to one shown in cxadc.c | ||
| By default, cxadc captures unsigned 8-bit samples. Set this to 1 to | ||
| capture 10-bit samples, which will be returned as unsigned 16-bit | ||
| values. In 10-bit mode, the sample rate is halved. | ||
|
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||
| i) The output is saved in raw.pcm as 8 bit unsigned. | ||
| ### `tenxfsc` (0 or 1, default 0) | ||
|
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| j) stop the driver by using the command | ||
| By default, cxadc captures at a rate of 8 x fSc (8 * 315 / 88 Mhz, | ||
| approximately 28.6 MHz). Set this to 1 to capture at 10 x fSc | ||
| (approximately 35.8 MHz). | ||
|
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| rmmod cxadc | ||
| ### `vmux` (0 to 3, default 2) | ||
|
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| k) to get another capture , repeat e), g), and j). | ||
| (note this step might not be necessary but for the mean time, we'll | ||
| just stop and start the driver again to be safe). | ||
| Select the CX2388x input to capture. A typical TV card has the tuner, | ||
| composite input and S-Video inputs tied to three of these inputs; you | ||
| may need to experiment (or look at the cx88 source) to work out which | ||
| input you need. | ||
|
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||
| note : after installing driver, DMA is always running. To stop DMA, you need to remove driver | ||
| if you don't stop, you can run cxcap to capture again. | ||
| ## History | ||
|
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||
| ### 2005-09-25 - v0.2 | ||
|
|
||
| These codes runs are meant for Intel 32 bit single processor only. My machine is a Dell Pentium III | ||
| 800 MHz PC. | ||
| cxadc was originally written by Hew How Chee (<[email protected]>). | ||
| See [SDR using a CX2388x TV+FM card](http://web.archive.org/web/20091027150612/http://geocities.com/how_chee/cx23881fc6.htm) for more details. | ||
|
|
||
| /* | ||
| Make sure you log in as super user | ||
| - added support for i2c, use `i2c.c` to tune | ||
| - set registers to lower gain | ||
| - set registers so that no signal is nearer to sample value 128 | ||
| - added `vmux` and `audsel` as params during driver loading | ||
| (for 2nd IF hardware modification, load driver using `vmux=2`). | ||
| By default `audsel=2` is to route tv tuner audio signal to | ||
| audio out of TV card, `vmux=1` to use the signal from video in of tv card. | ||
|
|
||
| To compile : make | ||
| Output file : cxadc.ko | ||
| Create node : mknod /dev/cxadc c 126 0 | ||
| Install driver : insmod ./cxadc.ko | ||
| ### 2007-03-24 - v0.3 | ||
|
|
||
| read /dev/cxadc to get data | ||
| - change code to compile and run in kernel 2.6.18 (Fedora Core 6) | ||
| for Intel 32 bit single processor only | ||
| - clean up mess in version 0.2 code | ||
|
|
||
| Reference : btaudio driver, mc4020 driver , cxadc driver v0.3 | ||
| */ | ||
| ### 2013-12-18 - v0.4 | ||
|
|
||
| /* 'dmesg' log after insmod ./cxadc.ko (Addresses/Numbers might be different) | ||
| This version has been retargeted for Ubuntu 13.10 Linux 3.11 by | ||
| Chad Page (<[email protected]>). | ||
|
|
||
| If it is not something like this, then there might be memory allocation error. | ||
|
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| cxadc: mem addr 0xfd000000 size 0x0 | ||
| cxadc: risc inst buff allocated at virt 0xd4f40000 phy 0x14f40000 size 132 kbytes | ||
| cxadc: total DMA size allocated = 32768 kb | ||
| cxadc: end of risc inst 0xd4f6000c total size 128 kbyte | ||
| cxadc: IRQ used 11 | ||
| cxadc: MEM :fd000000 MMIO :d8f80000 | ||
| cxadc: dev 0x8800 (rev 5) at 02:0b.0, cxadc: irq: 11, latency: 255, mmio: 0xfd000000 | ||
| cxadc: char dev register ok | ||
| cxadc: audsel = 2 | ||
|
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||
| */ | ||
|
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||
| /* dmesg log after running cxcap to capture data | ||
| note that once cxadc driver is loaded, DMA is always running | ||
| to stop driver use 'rmmod cxadc' | ||
|
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||
| cxadc: open [0] private_data c7aa0000 | ||
| cxadc: vm end b7f8b000 vm start b5f8b000 size 2000000 | ||
| cxadc: vm pg off 0 | ||
| cxadc: mmap private data c7aa0000 | ||
| cxadc: enable interrupt | ||
| cxadc: release | ||
| */ | ||
|
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||
|
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||
|
|
||
| Version 0.2 or higher of the driver let you set the ADC input source during driver loading. Use "vmux=X" to do this, | ||
| X=0 to 3 | ||
| While still a mess, the driver has been simplified a bit. Data is now read | ||
| using standard `read()` semantics, so no capture program is needed like the original | ||
| version. | ||
|
|
||
| //vmux=2 is taken from 2nd IF (after hardware mod) | ||
| //vmux=1 is taken from video in | ||
| For the first time, it also runs on 64-bit Linux, and *seems* to be OK under | ||
| SMP. | ||
|
|
||
| On the Pixelview PlayTVPro Ultracard: | ||
| audsel: | ||
| 3=audio in to audio out | ||
| 2=fm stereo tuner out? | ||
| 1=silence ? | ||
| 0=tuner tv audio out? | ||
| ### 2019-06-09 - v0.5 | ||
|
|
||
| Hew How Chee | ||
| [email protected] | ||
| - Update to work with Linux 5.1; older versions should still work. | ||
| - Tidy up the code to get rid of most of the warnings from checkpatch, | ||
| and bring it closer in style to the normal cx88 driver. | ||
| - Make `audsel` optional. | ||
| - Don't allow `/dev/cxadc` to be opened multiple times. | ||
| - When unloading cxadc, reset the AGC registers to their default values. | ||
| as cx88 expects. This lets you switch between cxadc and cx88 without | ||
| rebooting. |