Blame view

RIOT/cpu/msp430fxyz/periph/timer.c 2.71 KB
a752c7ab   elopes   add first test an...
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
  /*
   * Copyright (C) 2015 Freie Universitรคt Berlin
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup     cpu_msp430fxyz
   * @ingroup     drivers_periph_timer
   * @{
   *
   * @file
   * @brief       Low-level timer driver implementation
   *
   * This implementation does only support one fixed timer, as defined in the
   * boards periph_conf.h file.
   *
   * @todo        Generalize to handle more timers and make them configurable
   *              through the board's `periph_conf.h`
   *
   * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
   *
   * @}
   */
  
  #include "cpu.h"
  #include "periph_cpu.h"
  #include "periph_conf.h"
  #include "periph/timer.h"
  
  /**
   * @brief   Save reference to the timer callback
   */
  static timer_cb_t isr_cb;
  
  /**
   * @brief    Save argument for the ISR callback
   */
  static void *isr_arg;
  
  
  int timer_init(tim_t dev, unsigned long freq, timer_cb_t cb, void *arg)
  {
      /* using fixed TIMER_BASE for now */
      if (dev != 0) {
          return -1;
      }
      /* TODO: configure time-base depending on freq value */
      if (freq != 1000000ul) {
          return -1;
      }
  
      /* reset the timer A configuration */
      TIMER_BASE->CTL = TIMER_CTL_CLR;
      /* save callback */
      isr_cb = cb;
      isr_arg = arg;
      /* configure timer to use the SMCLK with prescaler of 8 */
      TIMER_BASE->CTL = (TIMER_CTL_TASSEL_SMCLK | TIMER_CTL_ID_DIV8);
      /* configure CC channels */
      for (int i = 0; i < TIMER_CHAN; i++) {
          TIMER_BASE->CCTL[i] = 0;
      }
      /* start the timer in continuous mode */
      TIMER_BASE->CTL |= TIMER_CTL_MC_CONT;
      return 0;
  }
  
  int timer_set_absolute(tim_t dev, int channel, unsigned int value)
  {
      if (dev != 0 || channel > TIMER_CHAN) {
          return -1;
      }
      TIMER_BASE->CCR[channel] = value;
      TIMER_BASE->CCTL[channel] &= ~(TIMER_CCTL_CCIFG);
      TIMER_BASE->CCTL[channel] |=  (TIMER_CCTL_CCIE);
      return 0;
  }
  
  int timer_clear(tim_t dev, int channel)
  {
      if (dev != 0 || channel > TIMER_CHAN) {
          return -1;
      }
      TIMER_BASE->CCTL[channel] &= ~(TIMER_CCTL_CCIE);
      return 0;
  }
  
  unsigned int timer_read(tim_t dev)
  {
      return (unsigned int)TIMER_BASE->R;
  }
  
  void timer_start(tim_t dev)
  {
      TIMER_BASE->CTL |= TIMER_CTL_MC_CONT;
  }
  
  void timer_stop(tim_t dev)
  {
      TIMER_BASE->CTL &= ~(TIMER_CTL_MC_MASK);
  }
  
  ISR(TIMER_ISR_CC0, isr_timer_a_cc0)
  {
      __enter_isr();
  
      TIMER_BASE->CCTL[0] &= ~(TIMER_CCTL_CCIE);
      isr_cb(isr_arg, 0);
  
      __exit_isr();
  }
  
  ISR(TIMER_ISR_CCX, isr_timer_a_ccx)
  {
      __enter_isr();
  
      int chan = (int)(TIMER_IVEC->TAIV >> 1);
      TIMER_BASE->CCTL[chan] &= ~(TIMER_CCTL_CCIE);
      isr_cb(isr_arg, chan);
  
      __exit_isr();
  }