root / lab4 / i8254.h @ 322
History | View | Annotate | Download (2.43 KB)
1 |
#ifndef _LCOM_I8254_H_
|
---|---|
2 |
#define _LCOM_I8254_H_
|
3 |
|
4 |
#include <lcom/lcf.h> |
5 |
|
6 |
/** @defgroup i8254 i8254
|
7 |
* @{
|
8 |
*
|
9 |
* Constants for programming the i8254 Timer. Needs to be completed.
|
10 |
*/
|
11 |
|
12 |
#define TIMER_FREQ 1193182 /**< @brief clock frequency for timer in PC and AT */ |
13 |
#define TIMER_MIN_FREQ (TIMER_FREQ/UINT16_MAX) + ((TIMER_FREQ % UINT16_MAX) ? 1 : 0) /**< @brief mininum frequency for timer */ |
14 |
#define TIMER0_IRQ 0 /**< @brief Timer 0 IRQ line */ |
15 |
|
16 |
/* I/O port addresses */
|
17 |
|
18 |
#define TIMER_0 0x40 /**< @brief Timer 0 count register */ |
19 |
#define TIMER_1 0x41 /**< @brief Timer 1 count register */ |
20 |
#define TIMER_2 0x42 /**< @brief Timer 2 count register */ |
21 |
#define TIMER_CTRL 0x43 /**< @brief Control register */ |
22 |
|
23 |
#define SPEAKER_CTRL 0x61 /**< @brief Register for speaker control */ |
24 |
|
25 |
/* Timer control */
|
26 |
|
27 |
/* Timer selection: bits 7 and 6 */
|
28 |
|
29 |
#define TIMER_SEL0 0x00 /**< @brief Control Word for Timer 0 */ |
30 |
#define TIMER_SEL1 BIT(6) /**< @brief Control Word for Timer 1 */ |
31 |
#define TIMER_SEL2 BIT(7) /**< @brief Control Word for Timer 2 */ |
32 |
#define TIMER_RB_CMD (BIT(7) | BIT(6)) /**< @brief Read Back Command */ |
33 |
|
34 |
/* Register selection: bits 5 and 4 */
|
35 |
|
36 |
#define TIMER_LSB BIT(4) /**< @brief Initialize Counter LSB only */ |
37 |
#define TIMER_MSB BIT(5) /**< @brief Initialize Counter MSB only */ |
38 |
#define TIMER_LSB_MSB (TIMER_LSB | TIMER_MSB) /**< @brief Initialize LSB first and MSB afterwards */ |
39 |
#define TIMER_INMODE_MASK 0x30 //0011 0000 |
40 |
#define TIMER_INMODE_POS 4 |
41 |
|
42 |
/* Operating mode: bits 3, 2 and 1 */
|
43 |
|
44 |
#define TIMER_SQR_WAVE (BIT(2) | BIT(1)) /**< @brief Mode 3: square wave generator */ |
45 |
#define TIMER_RATE_GEN BIT(2) /**< @brief Mode 2: rate generator */ |
46 |
#define TIMER_MODE_MASK 0x0E /**< @brief Mask for mode */ |
47 |
#define TIMER_MODE_POS 1 /**< @brief Position of smallest bit from mode */ |
48 |
#define TIMER_MODE_2ALT 0x6 /**< @brief Alternative notation for mode 2 */ |
49 |
#define TIMER_MODE_3ALT 0x7 /**< @brief Alternative notation for mode 3 */ |
50 |
#define TIMER_MODE_RED2 0x03 /**< @brief Reduce 3-bit mode to 2-bit mode */ |
51 |
|
52 |
/* Counting mode: bit 0 */
|
53 |
|
54 |
#define TIMER_BCD 0x01 /**< @brief Count in BCD */ |
55 |
#define TIMER_BIN 0x00 /**< @brief Count in binary */ |
56 |
|
57 |
/* READ-BACK COMMAND FORMAT */
|
58 |
|
59 |
#define TIMER_RB_COUNT_ BIT(5) |
60 |
#define TIMER_RB_STATUS_ BIT(4) |
61 |
#define TIMER_RB_SEL(n) BIT((n) + 1) |
62 |
|
63 |
/**@}*/
|
64 |
|
65 |
#endif /* _LCOM_I8254_H */ |