root / lab2 / include / i8254.h @ 392
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| 1 | 196 | up20180642 | #ifndef _LCOM_I8254_H_
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| 2 | #define _LCOM_I8254_H_
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| 3 | |||
| 4 | /** @defgroup i8254 i8254
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| 5 | *
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| 6 | * Constants for programming the i8254 Timer. Needs to be completed.
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| 7 | */
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| 8 | |||
| 9 | #define TIMER_FREQ 1193182 /**< @brief clock frequency for timer in PC and AT */ |
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| 10 | #define TIMER_MIN_FREQ (TIMER_FREQ/UINT16_MAX) + ((TIMER_FREQ % UINT16_MAX) ? 1 : 0) /**< @brief mininum frequency for timer */ |
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| 11 | #define TIMER0_IRQ 0 /**< @brief Timer 0 IRQ line */ |
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| 12 | |||
| 13 | /* I/O port addresses */
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| 14 | |||
| 15 | #define TIMER_0 0x40 /**< @brief Timer 0 count register */ |
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| 16 | #define TIMER_1 0x41 /**< @brief Timer 1 count register */ |
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| 17 | #define TIMER_2 0x42 /**< @brief Timer 2 count register */ |
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| 18 | #define TIMER_CTRL 0x43 /**< @brief Control register */ |
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| 19 | |||
| 20 | #define SPEAKER_CTRL 0x61 /**< @brief Register for speaker control */ |
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| 21 | |||
| 22 | /* Timer control */
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| 23 | |||
| 24 | /* Timer selection: bits 7 and 6 */
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| 25 | |||
| 26 | #define TIMER_SEL0 0x00 /**< @brief Control Word for Timer 0 */ |
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| 27 | #define TIMER_SEL1 BIT(6) /**< @brief Control Word for Timer 1 */ |
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| 28 | #define TIMER_SEL2 BIT(7) /**< @brief Control Word for Timer 2 */ |
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| 29 | #define TIMER_RB_CMD (BIT(7) | BIT(6)) /**< @brief Read Back Command */ |
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| 30 | |||
| 31 | /* Register selection: bits 5 and 4 */
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| 32 | |||
| 33 | #define TIMER_LSB BIT(4) /**< @brief Initialize Counter LSB only */ |
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| 34 | #define TIMER_MSB BIT(5) /**< @brief Initialize Counter MSB only */ |
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| 35 | #define TIMER_LSB_MSB (TIMER_LSB | TIMER_MSB) /**< @brief Initialize LSB first and MSB afterwards */ |
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| 36 | #define TIMER_INMODE_MASK 0x30 /**< @brief Mask for Timer Counter Mode */ |
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| 37 | #define TIMER_INMODE_POS 4 /**< @brief Bit position of Timer Counter Mode */ |
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| 38 | |||
| 39 | /* Operating mode: bits 3, 2 and 1 */
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| 40 | |||
| 41 | #define TIMER_SQR_WAVE (BIT(2) | BIT(1)) /**< @brief Mode 3: square wave generator */ |
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| 42 | #define TIMER_RATE_GEN BIT(2) /**< @brief Mode 2: rate generator */ |
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| 43 | #define TIMER_MODE_MASK 0x0E /**< @brief Mask for mode */ |
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| 44 | #define TIMER_MODE_POS 1 /**< @brief Position of smallest bit from mode */ |
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| 45 | #define TIMER_MODE_2ALT 0x6 /**< @brief Alternative notation for mode 2 */ |
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| 46 | #define TIMER_MODE_3ALT 0x7 /**< @brief Alternative notation for mode 3 */ |
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| 47 | #define TIMER_MODE_RED2 0x03 /**< @brief Reduce 3-bit mode to 2-bit mode */ |
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| 48 | |||
| 49 | /* Counting mode: bit 0 */
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| 50 | |||
| 51 | #define TIMER_BCD 0x01 /**< @brief Count in BCD */ |
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| 52 | #define TIMER_BIN 0x00 /**< @brief Count in binary */ |
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| 53 | |||
| 54 | /* READ-BACK COMMAND FORMAT */
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| 55 | |||
| 56 | #define TIMER_RB_COUNT_ BIT(5) /**< @brief Read counter value on read-back (0 to activate) */ |
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| 57 | #define TIMER_RB_STATUS_ BIT(4) /**< @brief Read status value on read-back (0 to activate) */ |
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| 58 | #define TIMER_RB_SEL(n) BIT((n) + 1) /**< @brief Select timer to read information from */ |
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| 59 | |||
| 60 | /**@}*/
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| 61 | |||
| 62 | #endif /* _LCOM_I8254_H */ |