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cx88.rst

cx88.rst 4.7 KB
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  1. The cx88 driver
    2. 

  2. ===============
    3. 

  3. 

  4. Author:  Gerd Hoffmann
    5. 

  5. 

  6. This is a v4l2 device driver for the cx2388x chip.
    7. 

  7. 

  8. 

  9. Current status
    10. 

  10. --------------
    11. 

  11. 

  12. video
    13. 

  13. 	- Works.
    14. 

  14. 	- Overlay isn't supported.
    15. 

  15. 

  16. audio
    17. 

  17. 	- Works. The TV standard detection is made by the driver, as the
    18. 

  18. 	  hardware has bugs to auto-detect.
    19. 

  19. 	- audio data dma (i.e. recording without loopback cable to the
    20. 

  20. 	  sound card) is supported via cx88-alsa.
    21. 

  21. 

  22. vbi
    23. 

  23. 	- Works.
    24. 

  24. 

  25. 

  26. How to add support for new cards
    27. 

  27. --------------------------------
    28. 

  28. 

  29. The driver needs some config info for the TV cards.  This stuff is in
    30. 

  30. cx88-cards.c.  If the driver doesn't work well you likely need a new
    31. 

  31. entry for your card in that file.  Check the kernel log (using dmesg)
    32. 

  32. to see whenever the driver knows your card or not.  There is a line
    33. 

  33. like this one:
    34. 

  34. 

  35. .. code-block:: none
    36. 

  36. 

  37. 	cx8800[0]: subsystem: 0070:3400, board: Hauppauge WinTV \
    38. 

  38. 		34xxx models [card=1,autodetected]
    39. 

  39. 

  40. If your card is listed as "board: UNKNOWN/GENERIC" it is unknown to
    41. 

  41. the driver.  What to do then?
    42. 

  42. 

  43. 1) Try upgrading to the latest snapshot, maybe it has been added
    44. 

  44.    meanwhile.
    45. 

  45. 2) You can try to create a new entry yourself, have a look at
    46. 

  46.    cx88-cards.c.  If that worked, mail me your changes as unified
    47. 

  47.    diff ("diff -u").
    48. 

  48. 3) Or you can mail me the config information.  We need at least the
    49. 

  49.    following information to add the card:
    50. 

  50. 

  51.      - the PCI Subsystem ID ("0070:3400" from the line above,
    52. 

  52.        "lspci -v" output is fine too).
    53. 

  53.      - the tuner type used by the card.  You can try to find one by
    54. 

  54.        trial-and-error using the tuner=<n> insmod option.  If you
    55. 

  55.        know which one the card has you can also have a look at the
    56. 

  56.        list in CARDLIST.tuner
    57. 

  57. 

  58. Documentation missing at the cx88 datasheet
    59. 

  59. -------------------------------------------
    60. 

  60. 

  61. MO_OUTPUT_FORMAT (0x310164)
    62. 

  62. 

  63. .. code-block:: none
    64. 

  64. 

  65.   Previous default from DScaler: 0x1c1f0008
    66. 

  66.   Digit 8: 31-28
    67. 

  67.   28: PREVREMOD = 1
    68. 

  68. 

  69.   Digit 7: 27-24 (0xc = 12 = b1100 )
    70. 

  70.   27: COMBALT = 1
    71. 

  71.   26: PAL_INV_PHASE
    72. 

  72.     (DScaler apparently set this to 1, resulted in sucky picture)
    73. 

  73. 

  74.   Digits 6,5: 23-16
    75. 

  75.   25-16: COMB_RANGE = 0x1f [default] (9 bits -> max 512)
    76. 

  76. 

  77.   Digit 4: 15-12
    78. 

  78.   15: DISIFX = 0
    79. 

  79.   14: INVCBF = 0
    80. 

  80.   13: DISADAPT = 0
    81. 

  81.   12: NARROWADAPT = 0
    82. 

  82. 

  83.   Digit 3: 11-8
    84. 

  84.   11: FORCE2H
    85. 

  85.   10: FORCEREMD
    86. 

  86.   9: NCHROMAEN
    87. 

  87.   8: NREMODEN
    88. 

  88. 

  89.   Digit 2: 7-4
    90. 

  90.   7-6: YCORE
    91. 

  91.   5-4: CCORE
    92. 

  92. 

  93.   Digit 1: 3-0
    94. 

  94.   3: RANGE = 1
    95. 

  95.   2: HACTEXT
    96. 

  96.   1: HSFMT
    97. 

  97. 

  98. 0x47 is the sync byte for MPEG-2 transport stream packets.
    99. 

  99. Datasheet incorrectly states to use 47 decimal. 188 is the length.
    100. 

  100. All DVB compliant frontends output packets with this start code.
    101. 

  101. 

  102. Hauppauge WinTV cx88 IR information
    103. 

  103. -----------------------------------
    104. 

  104. 

  105. The controls for the mux are GPIO [0,1] for source, and GPIO 2 for muting.
    106. 

  106. 

  107. ====== ======== =================================================
    108. 

  108. GPIO0  GPIO1
    109. 

  109. ====== ======== =================================================
    110. 

  110.   0        0    TV Audio
    111. 

  111.   1        0    FM radio
    112. 

  112.   0        1    Line-In
    113. 

  113.   1        1    Mono tuner bypass or CD passthru (tuner specific)
    114. 

  114. ====== ======== =================================================
    115. 

  115. 

  116. GPIO 16(I believe) is tied to the IR port (if present).
    117. 

  117. 

  118. 

  119. From the data sheet:
    120. 

  120. 

  121. - Register 24'h20004  PCI Interrupt Status
    122. 

  122. 

  123.  - bit [18]  IR_SMP_INT Set when 32 input samples have been collected over
    124. 

  124.  - gpio[16] pin into GP_SAMPLE register.
    125. 

  125. 

  126. What's missing from the data sheet:
    127. 

  127. 

  128. - Setup 4KHz sampling rate (roughly 2x oversampled; good enough for our RC5
    129. 

  129.   compat remote)
    130. 

  130. - set register 0x35C050 to  0xa80a80
    131. 

  131. - enable sampling
    132. 

  132. - set register 0x35C054 to 0x5
    133. 

  133. - enable the IRQ bit 18 in the interrupt mask register (and
    134. 

  134.   provide for a handler)
    135. 

  135. 

  136. GP_SAMPLE register is at 0x35C058
    137. 

  137. 

  138. Bits are then right shifted into the GP_SAMPLE register at the specified
    139. 

  139. rate; you get an interrupt when a full DWORD is received.
    140. 

  140. You need to recover the actual RC5 bits out of the (oversampled) IR sensor
    141. 

  141. bits. (Hint: look for the 0/1and 1/0 crossings of the RC5 bi-phase data)  An
    142. 

  142. actual raw RC5 code will span 2-3 DWORDS, depending on the actual alignment.
    143. 

  143. 

  144. I'm pretty sure when no IR signal is present the receiver is always in a
    145. 

  145. marking state(1); but stray light, etc can cause intermittent noise values
    146. 

  146. as well.  Remember, this is a free running sample of the IR receiver state
    147. 

  147. over time, so don't assume any sample starts at any particular place.
    148. 

  148. 

  149. Additional info
    150. 

  150. ~~~~~~~~~~~~~~~
    151. 

  151. 

  152. This data sheet (google search) seems to have a lovely description of the
    153. 

  153. RC5 basics:
    154. 

  154. http://www.atmel.com/dyn/resources/prod_documents/doc2817.pdf
    155. 

  155. 

  156. This document has more data:
    157. 

  157. http://www.nenya.be/beor/electronics/rc5.htm
    158. 

  158. 

  159. This document has a  how to decode a bi-phase data stream:
    160. 

  160. http://www.ee.washington.edu/circuit_archive/text/ir_decode.txt
    161. 

  161. 

  162. This document has still more info:
    163. 

  163. http://www.xs4all.nl/~sbp/knowledge/ir/rc5.htm
    164.