root / lab2 / include / i8254.h @ 344
History | View | Annotate | Download (2.87 KB)
1 |
#ifndef _LCOM_I8254_H_
|
---|---|
2 |
#define _LCOM_I8254_H_
|
3 |
|
4 |
/** @defgroup i8254 i8254
|
5 |
*
|
6 |
* Constants for programming the i8254 Timer. Needs to be completed.
|
7 |
*/
|
8 |
|
9 |
#define TIMER_FREQ 1193182 /**< @brief clock frequency for timer in PC and AT */ |
10 |
#define TIMER_MIN_FREQ (TIMER_FREQ/UINT16_MAX) + ((TIMER_FREQ % UINT16_MAX) ? 1 : 0) /**< @brief mininum frequency for timer */ |
11 |
#define TIMER0_IRQ 0 /**< @brief Timer 0 IRQ line */ |
12 |
|
13 |
/* I/O port addresses */
|
14 |
|
15 |
#define TIMER_0 0x40 /**< @brief Timer 0 count register */ |
16 |
#define TIMER_1 0x41 /**< @brief Timer 1 count register */ |
17 |
#define TIMER_2 0x42 /**< @brief Timer 2 count register */ |
18 |
#define TIMER_CTRL 0x43 /**< @brief Control register */ |
19 |
|
20 |
#define SPEAKER_CTRL 0x61 /**< @brief Register for speaker control */ |
21 |
|
22 |
/* Timer control */
|
23 |
|
24 |
/* Timer selection: bits 7 and 6 */
|
25 |
|
26 |
#define TIMER_SEL0 0x00 /**< @brief Control Word for Timer 0 */ |
27 |
#define TIMER_SEL1 BIT(6) /**< @brief Control Word for Timer 1 */ |
28 |
#define TIMER_SEL2 BIT(7) /**< @brief Control Word for Timer 2 */ |
29 |
#define TIMER_RB_CMD (BIT(7) | BIT(6)) /**< @brief Read Back Command */ |
30 |
|
31 |
/* Register selection: bits 5 and 4 */
|
32 |
|
33 |
#define TIMER_LSB BIT(4) /**< @brief Initialize Counter LSB only */ |
34 |
#define TIMER_MSB BIT(5) /**< @brief Initialize Counter MSB only */ |
35 |
#define TIMER_LSB_MSB (TIMER_LSB | TIMER_MSB) /**< @brief Initialize LSB first and MSB afterwards */ |
36 |
#define TIMER_INMODE_MASK 0x30 /**< @brief Mask for Timer Counter Mode */ |
37 |
#define TIMER_INMODE_POS 4 /**< @brief Bit position of Timer Counter Mode */ |
38 |
|
39 |
/* Operating mode: bits 3, 2 and 1 */
|
40 |
|
41 |
#define TIMER_SQR_WAVE (BIT(2) | BIT(1)) /**< @brief Mode 3: square wave generator */ |
42 |
#define TIMER_RATE_GEN BIT(2) /**< @brief Mode 2: rate generator */ |
43 |
#define TIMER_MODE_MASK 0x0E /**< @brief Mask for mode */ |
44 |
#define TIMER_MODE_POS 1 /**< @brief Position of smallest bit from mode */ |
45 |
#define TIMER_MODE_2ALT 0x6 /**< @brief Alternative notation for mode 2 */ |
46 |
#define TIMER_MODE_3ALT 0x7 /**< @brief Alternative notation for mode 3 */ |
47 |
#define TIMER_MODE_RED2 0x03 /**< @brief Reduce 3-bit mode to 2-bit mode */ |
48 |
|
49 |
/* Counting mode: bit 0 */
|
50 |
|
51 |
#define TIMER_BCD 0x01 /**< @brief Count in BCD */ |
52 |
#define TIMER_BIN 0x00 /**< @brief Count in binary */ |
53 |
|
54 |
/* READ-BACK COMMAND FORMAT */
|
55 |
|
56 |
#define TIMER_RB_COUNT_ BIT(5) /**< @brief Read counter value on read-back (0 to activate) */ |
57 |
#define TIMER_RB_STATUS_ BIT(4) /**< @brief Read status value on read-back (0 to activate) */ |
58 |
#define TIMER_RB_SEL(n) BIT((n) + 1) /**< @brief Select timer to read information from */ |
59 |
|
60 |
/**@}*/
|
61 |
|
62 |
#endif /* _LCOM_I8254_H */ |