Hauppauge WinTV PVR Board info
The board itself consists of the following chips:

* Conexant 878A
* Kfir01
* Altera flex EPF6016ATC144-3
* Philips SAA7113H
* Micronas MSP3415D B3
* Analog Devices ADSP-2185M
* C16C54C
* Microclock MK2745-20S
* Philips FM1216/I Tuner

The Bt878A acts as a PCI bridge for the Kfir chip. All communication to the Kfir is done through the GPIO pins of the bttv. A programmable Gate array chip (Altera Flex 6016) is used to provide the connections between the Kfir, Bt878A GPIO pins, ADSP and clock chip.

The Bt878A and the Altera chip have the following connections:
Bt878A Pin Function Altera Pin Function
86 GPIO 0 124/125 General Logic / Data
85 GPIO 1 122 General Logic
84 GPIO 2 121 General Logic
83 GPIO 3 119 General Logic
82 GPIO 4 118 General Logic
81 GPIO 5 116 General Logic
80 GPIO 6 115 General Logic
79 GPIO 7 113 General Logic
78 GPIO 8 112 General Logic
77 GPIO 9 110 General Logic
76 GPIO 10 109 General Logic
75 GPIO 11 108 General Logic
72 GPIO 12 106 General Logic
71 GPIO 13 101 General Logic
70 GPIO 14 99 General Logic
69 GPIO 15 98 General Logic
68 GPIO 16 96 General Logic
67 GPIO 17 96 General Logic
61 GPIO 18 95 General Logic
60 GPIO 19 93 General Logic
59 GPIO 20 128 DCLK
58 GPIO 21 87 General Logic
57 GPIO 22 86 General Logic
56 GPIO 23 53 nConfig

The DATA, DLCK and nConfig pins are used to configure the altera. Once the altera is configured, the GPIO pins 0 to 15 are used as a 16 bit databus. The GPIO pins 16,17,18,19,21,22 are used as control pins. I'm still investigating the exact functions of the control pins.