deepstone
annotate src/pit8254.h @ 24:ad6b185723cd
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| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Sat, 21 Sep 2013 20:18:28 +0300 |
| parents | |
| children |
| rev | line source |
|---|---|
| nuclear@0 | 1 #ifndef PIT8254_H_ |
| nuclear@0 | 2 #define PIT8254_H_ |
| nuclear@0 | 3 |
| nuclear@0 | 4 /* frequency of the oscillator driving the 8254 timer */ |
| nuclear@0 | 5 #define OSC_FREQ_HZ 1193182 |
| nuclear@0 | 6 |
| nuclear@0 | 7 /* I/O ports connected to the 8254 */ |
| nuclear@0 | 8 #define PORT_DATA0 0x40 |
| nuclear@0 | 9 #define PORT_DATA1 0x41 |
| nuclear@0 | 10 #define PORT_DATA2 0x42 |
| nuclear@0 | 11 #define PORT_CMD 0x43 |
| nuclear@0 | 12 |
| nuclear@0 | 13 /* command bits */ |
| nuclear@0 | 14 #define CMD_CHAN0 0 |
| nuclear@0 | 15 #define CMD_CHAN1 (1 << 6) |
| nuclear@0 | 16 #define CMD_CHAN2 (2 << 6) |
| nuclear@0 | 17 #define CMD_RDBACK (3 << 6) |
| nuclear@0 | 18 |
| nuclear@0 | 19 #define CMD_LATCH 0 |
| nuclear@0 | 20 #define CMD_ACCESS_LOW (1 << 4) |
| nuclear@0 | 21 #define CMD_ACCESS_HIGH (2 << 4) |
| nuclear@0 | 22 #define CMD_ACCESS_BOTH (3 << 4) |
| nuclear@0 | 23 |
| nuclear@0 | 24 #define CMD_OP_INT_TERM 0 |
| nuclear@0 | 25 #define CMD_OP_ONESHOT (1 << 1) |
| nuclear@0 | 26 #define CMD_OP_RATE (2 << 1) |
| nuclear@0 | 27 #define CMD_OP_SQWAVE (3 << 1) |
| nuclear@0 | 28 #define CMD_OP_SW_STROBE (4 << 1) |
| nuclear@0 | 29 #define CMD_OP_HW_STROBE (5 << 1) |
| nuclear@0 | 30 |
| nuclear@0 | 31 #define CMD_MODE_BIN 0 |
| nuclear@0 | 32 #define CMD_MODE_BCD 1 |
| nuclear@0 | 33 |
| nuclear@0 | 34 #endif /* PIT8254_H_ */ |