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
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
|
/*
* FreeRTOS V202111.00
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* 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.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/*
* Basic task to demonstrate the xQueueOverwrite() function. See the comments
* in the function itself.
*/
/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
/* Demo program include files. */
#include "QueueOverwrite.h"
/* A block time of 0 just means "don't block". */
#define qoDONT_BLOCK 0
/* Number of times to overwrite the value in the queue. */
#define qoLOOPS 5
/* The task that uses the queue. */
static void prvQueueOverwriteTask( void * pvParameters );
/* Variable that is incremented on each loop of prvQueueOverwriteTask() provided
* prvQueueOverwriteTask() has not found any errors. */
static uint32_t ulLoopCounter = 0;
/* Set to pdFALSE if an error is discovered by the
* vQueueOverwritePeriodicISRDemo() function. */
static BaseType_t xISRTestStatus = pdPASS;
/* The queue that is accessed from the ISR. The queue accessed by the task is
* created inside the task itself. */
static QueueHandle_t xISRQueue = NULL;
/*-----------------------------------------------------------*/
void vStartQueueOverwriteTask( UBaseType_t uxPriority )
{
const UBaseType_t uxQueueLength = 1;
/* Create the queue used by the ISR. xQueueOverwriteFromISR() should only
* be used on queues that have a length of 1. */
xISRQueue = xQueueCreate( uxQueueLength, ( UBaseType_t ) sizeof( uint32_t ) );
/* Create the test task. The queue used by the test task is created inside
* the task itself. */
xTaskCreate( prvQueueOverwriteTask, "QOver", configMINIMAL_STACK_SIZE, NULL, uxPriority, ( TaskHandle_t * ) NULL );
}
/*-----------------------------------------------------------*/
static void prvQueueOverwriteTask( void * pvParameters )
{
QueueHandle_t xTaskQueue;
const UBaseType_t uxQueueLength = 1;
uint32_t ulValue, ulStatus = pdPASS, x;
/* The parameter is not used. */
( void ) pvParameters;
/* Create the queue. xQueueOverwrite() should only be used on queues that
* have a length of 1. */
xTaskQueue = xQueueCreate( uxQueueLength, ( UBaseType_t ) sizeof( uint32_t ) );
configASSERT( xTaskQueue );
for( ; ; )
{
/* The queue is empty. Writing to the queue then reading from the queue
* should return the item written. */
ulValue = 10;
xQueueOverwrite( xTaskQueue, &ulValue );
ulValue = 0;
xQueueReceive( xTaskQueue, &ulValue, qoDONT_BLOCK );
if( ulValue != 10 )
{
ulStatus = pdFAIL;
}
/* Now try writing to the queue several times. Each time the value
* in the queue should get overwritten. */
for( x = 0; x < qoLOOPS; x++ )
{
/* Write to the queue. */
xQueueOverwrite( xTaskQueue, &x );
/* Check the value in the queue is that written, even though the
* queue was not necessarily empty. */
xQueuePeek( xTaskQueue, &ulValue, qoDONT_BLOCK );
if( ulValue != x )
{
ulStatus = pdFAIL;
}
/* There should always be one item in the queue. */
if( uxQueueMessagesWaiting( xTaskQueue ) != uxQueueLength )
{
ulStatus = pdFAIL;
}
}
/* Empty the queue again. */
xQueueReceive( xTaskQueue, &ulValue, qoDONT_BLOCK );
if( uxQueueMessagesWaiting( xTaskQueue ) != 0 )
{
ulStatus = pdFAIL;
}
if( ulStatus != pdFAIL )
{
/* Increment a counter to show this task is still running without
* error. */
ulLoopCounter++;
}
#if ( configUSE_PREEMPTION == 0 )
taskYIELD();
#endif
}
}
/*-----------------------------------------------------------*/
BaseType_t xIsQueueOverwriteTaskStillRunning( void )
{
BaseType_t xReturn;
if( xISRTestStatus != pdPASS )
{
xReturn = pdFAIL;
}
else if( ulLoopCounter > 0 )
{
xReturn = pdPASS;
}
else
{
/* The task has either stalled of discovered an error. */
xReturn = pdFAIL;
}
ulLoopCounter = 0;
return xReturn;
}
/*-----------------------------------------------------------*/
void vQueueOverwritePeriodicISRDemo( void )
{
static uint32_t ulCallCount = 0;
const uint32_t ulTx1 = 10UL, ulTx2 = 20UL, ulNumberOfSwitchCases = 3UL;
uint32_t ulRx;
/* This function should be called from an interrupt, such as the tick hook
* function vApplicationTickHook(). */
configASSERT( xISRQueue );
switch( ulCallCount )
{
case 0:
/* The queue is empty. Write ulTx1 to the queue. In this demo the
* last parameter is not used because there are no tasks blocked on
* this queue. */
xQueueOverwriteFromISR( xISRQueue, &ulTx1, NULL );
/* Peek the queue to check it holds the expected value. */
xQueuePeekFromISR( xISRQueue, &ulRx );
if( ulRx != ulTx1 )
{
xISRTestStatus = pdFAIL;
}
break;
case 1:
/* The queue already holds ulTx1. Overwrite the value in the queue
* with ulTx2. */
xQueueOverwriteFromISR( xISRQueue, &ulTx2, NULL );
break;
case 2:
/* Read from the queue to empty the queue again. The value read
* should be ulTx2. */
xQueueReceiveFromISR( xISRQueue, &ulRx, NULL );
if( ulRx != ulTx2 )
{
xISRTestStatus = pdFAIL;
}
break;
}
/* Run the next case in the switch statement above next time this function
* is called. */
ulCallCount++;
if( ulCallCount >= ulNumberOfSwitchCases )
{
/* Go back to the start. */
ulCallCount = 0;
}
}
|
