| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113 |
- .. SPDX-License-Identifier: GPL-2.0
- The cx88 driver
- ===============
- Author: Gerd Hoffmann
- Documentation missing at the cx88 datasheet
- -------------------------------------------
- MO_OUTPUT_FORMAT (0x310164)
- .. code-block:: none
- Previous default from DScaler: 0x1c1f0008
- Digit 8: 31-28
- 28: PREVREMOD = 1
- Digit 7: 27-24 (0xc = 12 = b1100 )
- 27: COMBALT = 1
- 26: PAL_INV_PHASE
- (DScaler apparently set this to 1, resulted in sucky picture)
- Digits 6,5: 23-16
- 25-16: COMB_RANGE = 0x1f [default] (9 bits -> max 512)
- Digit 4: 15-12
- 15: DISIFX = 0
- 14: INVCBF = 0
- 13: DISADAPT = 0
- 12: NARROWADAPT = 0
- Digit 3: 11-8
- 11: FORCE2H
- 10: FORCEREMD
- 9: NCHROMAEN
- 8: NREMODEN
- Digit 2: 7-4
- 7-6: YCORE
- 5-4: CCORE
- Digit 1: 3-0
- 3: RANGE = 1
- 2: HACTEXT
- 1: HSFMT
- 0x47 is the sync byte for MPEG-2 transport stream packets.
- Datasheet incorrectly states to use 47 decimal. 188 is the length.
- All DVB compliant frontends output packets with this start code.
- Hauppauge WinTV cx88 IR information
- -----------------------------------
- The controls for the mux are GPIO [0,1] for source, and GPIO 2 for muting.
- ====== ======== =================================================
- GPIO0 GPIO1
- ====== ======== =================================================
- 0 0 TV Audio
- 1 0 FM radio
- 0 1 Line-In
- 1 1 Mono tuner bypass or CD passthru (tuner specific)
- ====== ======== =================================================
- GPIO 16(I believe) is tied to the IR port (if present).
- From the data sheet:
- - Register 24'h20004 PCI Interrupt Status
- - bit [18] IR_SMP_INT Set when 32 input samples have been collected over
- - gpio[16] pin into GP_SAMPLE register.
- What's missing from the data sheet:
- - Setup 4KHz sampling rate (roughly 2x oversampled; good enough for our RC5
- compat remote)
- - set register 0x35C050 to 0xa80a80
- - enable sampling
- - set register 0x35C054 to 0x5
- - enable the IRQ bit 18 in the interrupt mask register (and
- provide for a handler)
- GP_SAMPLE register is at 0x35C058
- Bits are then right shifted into the GP_SAMPLE register at the specified
- rate; you get an interrupt when a full DWORD is received.
- You need to recover the actual RC5 bits out of the (oversampled) IR sensor
- bits. (Hint: look for the 0/1and 1/0 crossings of the RC5 bi-phase data) An
- actual raw RC5 code will span 2-3 DWORDS, depending on the actual alignment.
- I'm pretty sure when no IR signal is present the receiver is always in a
- marking state(1); but stray light, etc can cause intermittent noise values
- as well. Remember, this is a free running sample of the IR receiver state
- over time, so don't assume any sample starts at any particular place.
- Additional info
- ~~~~~~~~~~~~~~~
- This data sheet (google search) seems to have a lovely description of the
- RC5 basics:
- http://www.atmel.com/dyn/resources/prod_documents/doc2817.pdf
- This document has more data:
- http://www.nenya.be/beor/electronics/rc5.htm
- This document has a how to decode a bi-phase data stream:
- http://www.ee.washington.edu/circuit_archive/text/ir_decode.txt
- This document has still more info:
- http://www.xs4all.nl/~sbp/knowledge/ir/rc5.htm
|
