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
160
161
162
163
164
165
166
167
168
169
170
|
/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Mark Shannon
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "stddef.h"
#include "lib/ticker.h"
#define FastTicker NRF_TIMER0
#define FastTicker_IRQn TIMER0_IRQn
#define FastTicker_IRQHandler TIMER0_IRQHandler
#define SlowTicker_IRQn SWI3_IRQn
#define SlowTicker_IRQHandler SWI3_IRQHandler
#define LowPriority_IRQn SWI4_IRQn
#define LowPriority_IRQHandler SWI4_IRQHandler
// The number of milliseconds that have passed since the ticker was initialised
volatile uint32_t ticker_ticks_ms;
// Ticker callback function called every MACRO_TICK
static callback_ptr slow_ticker;
void ticker_init(callback_ptr slow_ticker_callback) {
ticker_ticks_ms = 0;
slow_ticker = slow_ticker_callback;
NRF_TIMER_Type *ticker = FastTicker;
ticker->POWER = 1;
__NOP();
ticker_stop();
ticker->TASKS_CLEAR = 1;
ticker->CC[3] = MICROSECONDS_PER_MACRO_TICK;
ticker->MODE = TIMER_MODE_MODE_Timer;
ticker->BITMODE = TIMER_BITMODE_BITMODE_24Bit << TIMER_BITMODE_BITMODE_Pos;
ticker->PRESCALER = 4; // 1 tick == 1 microsecond
ticker->INTENSET = TIMER_INTENSET_COMPARE3_Msk;
ticker->SHORTS = 0;
NVIC_SetPriority(FastTicker_IRQn, 1);
NVIC_SetPriority(SlowTicker_IRQn, 2);
NVIC_SetPriority(LowPriority_IRQn, 3);
NVIC_EnableIRQ(SlowTicker_IRQn);
NVIC_EnableIRQ(LowPriority_IRQn);
}
/* Start and stop timer 0 including workarounds for Anomaly 73 for Timer
* http://www.nordicsemi.com/eng/content/download/29490/494569/file/nRF51822-PAN%20v3.0.pdf
*/
void ticker_start(void) {
NVIC_EnableIRQ(FastTicker_IRQn);
*(uint32_t *)0x40008C0C = 1; //for Timer 0
FastTicker->TASKS_START = 1;
}
void ticker_stop(void) {
NVIC_DisableIRQ(FastTicker_IRQn);
FastTicker->TASKS_STOP = 1;
*(uint32_t *)0x40008C0C = 0; //for Timer 0
}
int32_t noop(void) {
return -1;
}
static ticker_callback_ptr callbacks[3] = { noop, noop, noop };
void FastTicker_IRQHandler(void) {
NRF_TIMER_Type *ticker = FastTicker;
ticker_callback_ptr *call = callbacks;
if (ticker->EVENTS_COMPARE[0]) {
ticker->EVENTS_COMPARE[0] = 0;
ticker->CC[0] += call[0]()*MICROSECONDS_PER_TICK;
}
if (ticker->EVENTS_COMPARE[1]) {
ticker->EVENTS_COMPARE[1] = 0;
ticker->CC[1] += call[1]()*MICROSECONDS_PER_TICK;
}
if (ticker->EVENTS_COMPARE[2]) {
ticker->EVENTS_COMPARE[2] = 0;
ticker->CC[2] += call[2]()*MICROSECONDS_PER_TICK;
}
if (ticker->EVENTS_COMPARE[3]) {
ticker->EVENTS_COMPARE[3] = 0;
ticker->CC[3] += MICROSECONDS_PER_MACRO_TICK;
ticker_ticks_ms += MILLISECONDS_PER_MACRO_TICK;
NVIC_SetPendingIRQ(SlowTicker_IRQn);
}
}
static const uint32_t masks[3] = {
TIMER_INTENCLR_COMPARE0_Msk,
TIMER_INTENCLR_COMPARE1_Msk,
TIMER_INTENCLR_COMPARE2_Msk,
};
int set_ticker_callback(uint32_t index, ticker_callback_ptr func, int32_t initial_delay_us) {
if (index > 3)
return -1;
NRF_TIMER_Type *ticker = FastTicker;
callbacks[index] = noop;
ticker->INTENCLR = masks[index];
ticker->TASKS_CAPTURE[index] = 1;
uint32_t t = FastTicker->CC[index];
// Need to make sure that set tick is aligned to lastest tick
// Use CC[3] as a reference, as that is always up-to-date.
int32_t cc3 = FastTicker->CC[3];
int32_t delta = t+initial_delay_us-cc3;
delta = (delta/MICROSECONDS_PER_TICK+1)*MICROSECONDS_PER_TICK;
callbacks[index] = func;
ticker->INTENSET = masks[index];
FastTicker->CC[index] = cc3 + delta;
return 0;
}
int clear_ticker_callback(uint32_t index) {
if (index > 3)
return -1;
FastTicker->INTENCLR = masks[index];
callbacks[index] = noop;
return 0;
}
void SlowTicker_IRQHandler(void)
{
slow_ticker();
}
#define LOW_PRIORITY_CALLBACK_LIMIT 4
callback_ptr low_priority_callbacks[LOW_PRIORITY_CALLBACK_LIMIT] = { NULL, NULL, NULL, NULL };
void LowPriority_IRQHandler(void)
{
for (int id = 0; id < LOW_PRIORITY_CALLBACK_LIMIT; id++) {
callback_ptr callback = low_priority_callbacks[id];
if (callback != NULL) {
low_priority_callbacks[id] = NULL;
callback();
}
}
}
int set_low_priority_callback(callback_ptr callback, int id) {
if (low_priority_callbacks[id] != NULL)
return -1;
low_priority_callbacks[id] = callback;
NVIC_SetPendingIRQ(LowPriority_IRQn);
return 0;
}
|
