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| A driver for a selfmade cheap BT8xx based PCI GPIO-card (bt8xxgpio) |
| =================================================================== |
| |
| For advanced documentation, see http://www.bu3sch.de/btgpio.php |
| |
| A generic digital 24-port PCI GPIO card can be built out of an ordinary |
| Brooktree bt848, bt849, bt878 or bt879 based analog TV tuner card. The |
| Brooktree chip is used in old analog Hauppauge WinTV PCI cards. You can easily |
| find them used for low prices on the net. |
| |
| The bt8xx chip does have 24 digital GPIO ports. |
| These ports are accessible via 24 pins on the SMD chip package. |
| |
| |
| How to physically access the GPIO pins |
| ====================================== |
| |
| The are several ways to access these pins. One might unsolder the whole chip |
| and put it on a custom PCI board, or one might only unsolder each individual |
| GPIO pin and solder that to some tiny wire. As the chip package really is tiny |
| there are some advanced soldering skills needed in any case. |
| |
| The physical pinouts are drawn in the following ASCII art. |
| The GPIO pins are marked with G00-G23:: |
| |
| G G G G G G G G G G G G G G G G G G |
| 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 |
| 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| --------------------------------------------------------------------------- |
| --| ^ ^ |-- |
| --| pin 86 pin 67 |-- |
| --| |-- |
| --| pin 61 > |-- G18 |
| --| |-- G19 |
| --| |-- G20 |
| --| |-- G21 |
| --| |-- G22 |
| --| pin 56 > |-- G23 |
| --| |-- |
| --| Brooktree 878/879 |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| |-- |
| --| O |-- |
| --| |-- |
| --------------------------------------------------------------------------- |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| ^ |
| This is pin 1 |
| |