aboutsummaryrefslogtreecommitdiffstats
path: root/os/hal/ports/NRF51/NRF51822/st_lld.c
blob: a43a679d61eb352ca683efcd6aaaa45e843b7444 (plain)
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
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
/*
    ChibiOS - Copyright (C) 2015 Fabio Utzig
                            2016 Stephane D'Alu

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

/**
 * @file    st_lld.c
 * @brief   NRF51822 ST subsystem low level driver source.
 *
 * @addtogroup ST
 * @{
 */

#include "hal.h"

#if (OSAL_ST_MODE != OSAL_ST_MODE_NONE) || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver local definitions.                                                 */
/*===========================================================================*/

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local types.                                                       */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local variables and types.                                         */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver interrupt handlers.                                                */
/*===========================================================================*/

#if (OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC) || defined(__DOXYGEN__)

#if (NRF51_SYSTEM_TICKS == NRF51_SYSTEM_TICKS_AS_RTC)
/**
 * @brief   System Timer vector (RTC0)
 * @details This interrupt is used for system tick in periodic mode
 *          if selected with NRF51_SYSTEM_TICKS == NRF51_SYSTEM_TICKS_AS_RTC
 *
 * @isr
 */
OSAL_IRQ_HANDLER(Vector6C) {

  OSAL_IRQ_PROLOGUE();

  NRF_RTC0->EVENTS_TICK = 0;
      
  osalSysLockFromISR();
  osalOsTimerHandlerI();
  osalSysUnlockFromISR();

  OSAL_IRQ_EPILOGUE();
}
#endif

#if (NRF51_SYSTEM_TICKS == NRF51_SYSTEM_TICKS_AS_TIMER)
/**
 * @brief   System Timer vector. (TIMER0)
 * @details This interrupt is used for system tick in periodic mode
 *          if selected with NRF51_SYSTEM_TICKS == NRF51_SYSTEM_TICKS_AS_TIMER
 *
 * @isr
 */
OSAL_IRQ_HANDLER(Vector60) {

  OSAL_IRQ_PROLOGUE();

  /* Clear timer compare event */
  if (NRF_TIMER0->EVENTS_COMPARE[0] != 0)
    NRF_TIMER0->EVENTS_COMPARE[0] = 0;

  osalSysLockFromISR();
  osalOsTimerHandlerI();
  osalSysUnlockFromISR();

  OSAL_IRQ_EPILOGUE();
}
#endif

#endif /* OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC */

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   Low level ST driver initialization.
 *
 * @notapi
 */
void st_lld_init(void) {
#if (OSAL_ST_MODE == OSAL_ST_MODE_FREERUNNING)

#endif /* OSAL_ST_MODE == OSAL_ST_MODE_FREERUNNING */

#if OSAL_ST_MODE == OSAL_ST_MODE_PERIODIC

#if (NRF51_SYSTEM_TICKS == NRF51_SYSTEM_TICKS_AS_RTC)
  /* Using RTC with prescaler */
  NRF_RTC0->TASKS_STOP  = 1;
  NRF_RTC0->PRESCALER   = (NRF51_LFCLK_FREQUENCY / OSAL_ST_FREQUENCY) - 1; 
  NRF_RTC0->INTENSET    = RTC_INTENSET_TICK_Msk;

  /* Start timer */
  nvicEnableVector(RTC0_IRQn, 8);
  NRF_RTC0->TASKS_START = 1;
#endif

#if (NRF51_SYSTEM_TICKS == NRF51_SYSTEM_TICKS_AS_TIMER)
  NRF_TIMER0->TASKS_CLEAR = 1;

  /*
   * Using 32-bit mode with prescaler 16 configures this
   * timer with a 1MHz clock.
   */
  NRF_TIMER0->BITMODE = 3;
  NRF_TIMER0->PRESCALER = 4;

  /*
   * Configure timer 0 compare capture 0 to generate interrupt
   * and clear timer value when event is generated.
   */
  NRF_TIMER0->CC[0] = (1000000 / OSAL_ST_FREQUENCY) - 1;
  NRF_TIMER0->SHORTS = 1;
  NRF_TIMER0->INTENSET = 0x10000;

  /* Start timer */
  nvicEnableVector(TIMER0_IRQn, 8);
  NRF_TIMER0->TASKS_START = 1;
#endif

#endif
}

#endif /* OSAL_ST_MODE != OSAL_ST_MODE_NONE */

/** @} */