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
|
/*
* FreeRTOS Kernel V10.2.1
* Copyright (C) 2019 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 INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
*NOTE* - This file is designed to test some of the RTOS features - it is
not intended to represent an efficient implementation!
*/
/* Standard includes. */
#include <stdlib.h>
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
/* Demo application includes. */
#include "serial.h"
/* Hardware specifics. */
#define serRX_DATA_PIN ( 0x01 )
#define serTX_DATA_PIN ( 0x02 )
#define serCLOCK_Fxx_DIV_8 0x03
#define serUPWR ( 0x80 )
#define serUTXE ( 0x40 )
#define serURXE ( 0x20 )
#define serUCL ( 0x02 )
#define serLSB ( 0x10 )
/* Misc. */
#define serINVALID_QUEUE ( ( QueueHandle_t ) 0 )
#define serHANDLE ( ( xComPortHandle ) 1 )
#define serNO_BLOCK ( ( TickType_t ) 0 )
/*-----------------------------------------------------------*/
/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static QueueHandle_t xRxedChars;
static QueueHandle_t xCharsForTx;
/*-----------------------------------------------------------*/
/* Interrupt entry point written in the assembler file serialISR.s85. */
extern void vSerialISREntry( void );
/* Flag to indicate whether or not there are characters already queued to send. */
static volatile unsigned long ulTxInProgress = pdFALSE;
/*-----------------------------------------------------------*/
/*
* See the serial2.h header file.
*/
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
xComPortHandle xReturn = serHANDLE;
const unsigned long ulFuclk = ( configCPU_CLOCK_HZ / 2 ) / 8UL;
/* Create the queues used to hold Rx and Tx characters. */
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
/* If the queues were created correctly then setup the serial port
hardware. */
if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
{
portENTER_CRITICAL();
{
/* Set the UART0 Rx and Tx pins to their alternative function. */
PMC3 |= ( serRX_DATA_PIN | serTX_DATA_PIN );
PM3 &= ~( serTX_DATA_PIN );
/* Setup clock for required baud. */
UD0CTL1 = serCLOCK_Fxx_DIV_8;
UD0CTL2 = ulFuclk / ( 2 * ulWantedBaud );
/* Enable, n81. */
UD0CTL0 = ( serUPWR | serUTXE | serURXE | serUCL | serLSB );
/* Enable interrupts for both Rx and Tx. */
UD0TIC = 0x07;
UD0RIC = 0x07;
ulTxInProgress = pdFALSE;
}
portEXIT_CRITICAL();
}
else
{
xReturn = ( xComPortHandle ) 0;
}
/* This demo file only supports a single port but we have to return
something to comply with the standard demo header file. */
return xReturn;
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
{
/* The port handle is not required as this driver only supports one port. */
( void ) pxPort;
/* 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;
}
}
/*-----------------------------------------------------------*/
void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
{
signed char *pxNext;
/* A couple of parameters that this port does not use. */
( void ) usStringLength;
( void ) pxPort;
/* NOTE: This implementation does not handle the queue being full as no
block time is used! */
/* The port handle is not required as this driver only supports UART0. */
( void ) pxPort;
/* Send each character in the string, one at a time. */
pxNext = ( signed char * ) pcString;
while( *pxNext )
{
xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
pxNext++;
}
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
{
portBASE_TYPE xReturn = pdPASS;
portENTER_CRITICAL();
{
/* There are currently no characters queued up to send so write the
character directly to the UART. */
if( ulTxInProgress == pdFALSE )
{
UD0TX = cOutChar;
ulTxInProgress = pdTRUE;
}
else
{
/* The UART is already busy so write the character to the Tx queue.
The queue is drained from within the Tx interrupt. */
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
{
xReturn = pdFAIL;
}
}
}
portEXIT_CRITICAL();
return xReturn;
}
/*-----------------------------------------------------------*/
void vSerialClose( xComPortHandle xPort )
{
/* Not supported as not required by the demo application. */
}
/*-----------------------------------------------------------*/
/* Tx interrupt handler. This is called from the asm file wrapper. */
void vUARTTxISRHandler( void )
{
char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* Are there any more characters queue to transmit? */
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
{
/* Send the next character. */
UD0TX = cChar;
}
else
{
/* The UART is no longer active. */
ulTxInProgress = pdFALSE;
}
/* If reading a character from the Rx queue caused a task to unblock, and
the unblocked task has a priority higher than the currently running task,
then xHigherPriorityTaskWoken will have been set to true and a context
switch should occur now. */
portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
}
/*-----------------------------------------------------------*/
/* Rx interrupt handler. This is called from the asm file wrapper. */
void vUARTRxISRHandler( void )
{
char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* Send the received character to the Rx queue. */
cChar = UD0RX;
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
/* If sending a character to the Tx queue caused a task to unblock, and
the unblocked task has a priority higher than the currently running task,
then xHigherPriorityTaskWoken will have been set to true and a context
switch should occur now. */
portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
}
|
