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
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
|
/*
FreeRTOS V7.4.0 - Copyright (C) 2013 Real Time Engineers Ltd.
FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
***************************************************************************
* *
* FreeRTOS tutorial books are available in pdf and paperback. *
* Complete, revised, and edited pdf reference manuals are also *
* available. *
* *
* Purchasing FreeRTOS documentation will not only help you, by *
* ensuring you get running as quickly as possible and with an *
* in-depth knowledge of how to use FreeRTOS, it will also help *
* the FreeRTOS project to continue with its mission of providing *
* professional grade, cross platform, de facto standard solutions *
* for microcontrollers - completely free of charge! *
* *
* >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
* *
* Thank you for using FreeRTOS, and thank you for your support! *
* *
***************************************************************************
This file is part of the FreeRTOS distribution.
FreeRTOS is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License (version 2) as published by the
Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
>>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
distribute a combined work that includes FreeRTOS without being obliged to
provide the source code for proprietary components outside of the FreeRTOS
kernel.
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details. You should have received a copy of the GNU General Public License
and the FreeRTOS license exception along with FreeRTOS; if not itcan be
viewed here: http://www.freertos.org/a00114.html and also obtained by
writing to Real Time Engineers Ltd., contact details for whom are available
on the FreeRTOS WEB site.
1 tab == 4 spaces!
***************************************************************************
* *
* Having a problem? Start by reading the FAQ "My application does *
* not run, what could be wrong?" *
* *
* http://www.FreeRTOS.org/FAQHelp.html *
* *
***************************************************************************
http://www.FreeRTOS.org - Documentation, books, training, latest versions,
license and Real Time Engineers Ltd. contact details.
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, and our new
fully thread aware and reentrant UDP/IP stack.
http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
Integrity Systems, who sell the code with commercial support,
indemnification and middleware, under the OpenRTOS brand.
http://www.SafeRTOS.com - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
*/
/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
*
* This file only supports UART 0
*/
/* Standard includes. */
#include <stdlib.h>
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"
/* Demo application includes. */
#include "serial.h"
/* The queue used to hold received characters. */
static xQueueHandle xRxedChars;
/* The queue used to hold characters waiting transmission. */
static xQueueHandle xCharsForTx;
static volatile portSHORT sTHREEmpty;
static volatile portSHORT queueFail = pdFALSE;
/*-----------------------------------------------------------*/
xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
/* Initialise the hardware. */
portENTER_CRITICAL();
{
/* Create the queues used by the com test task. */
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof(signed portCHAR) );
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof(signed portCHAR) );
if( xRxedChars == 0 )
{
queueFail = pdTRUE;
}
if( xCharsForTx == 0 )
{
queueFail = pdTRUE;
}
/* Initialize UART asynchronous mode */
BGR0 = configCLKP1_CLOCK_HZ / ulWantedBaud;
SCR0 = 0x17; /* 8N1 */
SMR0 = 0x0d; /* enable SOT3, Reset, normal mode */
SSR0 = 0x02; /* LSB first, enable receive interrupts */
PIER08_IE2 = 1; /* enable input */
DDR08_D2 = 0; /* switch P08_2 to input */
DDR08_D3 = 1; /* switch P08_3 to output */
}
portEXIT_CRITICAL();
/* Unlike other ports, this serial code does not allow for more than one
com port. We therefore don't return a pointer to a port structure and can
instead just return NULL. */
return NULL;
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
{
/* Get the next character from the buffer. Return false if no characters
are available, or arrive before xBlockTime expires. */
if( xQueueReceive(xRxedChars, pcRxedChar, xBlockTime) )
{
return pdTRUE;
}
else
{
return pdFALSE;
}
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
{
signed portBASE_TYPE xReturn;
/* Transmit a character. */
portENTER_CRITICAL();
{
if( sTHREEmpty == pdTRUE )
{
/* If sTHREEmpty is true then the UART Tx ISR has indicated that
there are no characters queued to be transmitted - so we can
write the character directly to the shift Tx register. */
sTHREEmpty = pdFALSE;
TDR0 = cOutChar;
xReturn = pdPASS;
}
else
{
/* sTHREEmpty is false, so there are still characters waiting to be
transmitted. We have to queue this character so it gets
transmitted in turn. */
/* Return false if after the block time there is no room on the Tx
queue. It is ok to block inside a critical section as each task
maintains it's own critical section status. */
if( xQueueSend(xCharsForTx, &cOutChar, xBlockTime) == pdTRUE )
{
xReturn = pdPASS;
}
else
{
xReturn = pdFAIL;
}
}
if( pdPASS == xReturn )
{
/* Turn on the Tx interrupt so the ISR will remove the character from the
queue and send it. This does not need to be in a critical section as
if the interrupt has already removed the character the next interrupt
will simply turn off the Tx interrupt again. */
SSR0_TIE = 1;
}
}
portEXIT_CRITICAL();
return pdPASS;
}
/*-----------------------------------------------------------*/
/*
* UART RX interrupt service routine.
*/
__interrupt void UART0_RxISR( void )
{
volatile signed portCHAR cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* Get the character from the UART and post it on the queue of Rxed
characters. */
cChar = RDR0;
xQueueSendFromISR( xRxedChars, ( const void *const ) &cChar, &xHigherPriorityTaskWoken );
if( xHigherPriorityTaskWoken )
{
/*If the post causes a task to wake force a context switch
as the woken task may have a higher priority than the task we have
interrupted. */
portYIELD_FROM_ISR();
}
}
/*-----------------------------------------------------------*/
/*
* UART Tx interrupt service routine.
*/
__interrupt void UART0_TxISR( void )
{
signed portCHAR cChar;
signed portBASE_TYPE xTaskWoken = pdFALSE;
/* The previous character has been transmitted. See if there are any
further characters waiting transmission. */
if( xQueueReceiveFromISR(xCharsForTx, &cChar, &xTaskWoken) == pdTRUE )
{
/* There was another character queued - transmit it now. */
TDR0 = cChar;
}
else
{
/* There were no other characters to transmit. */
sTHREEmpty = pdTRUE;
/* Disable transmit interrupts */
SSR0_TIE = 0;
}
}
|
