Project

General

Profile

Statistics
| Revision:

root / lab2 / i8254.h @ 24

History | View | Annotate | Download (2.37 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 19 /**< @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 */