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
|
/*
* 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.
*/
/* Standard includes. */
#include <stdlib.h>
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
/* Demo application includes. */
#include "serial.h"
/* Library includes. */
#include "usart/usart.h"
#include "pmc/pmc.h"
#include "irq/irq.h"
#include "pio/pio.h"
/*-----------------------------------------------------------*/
/* Interrupt control macros. */
#define serINTERRUPT_LEVEL ( 5 )
#define vInterruptOn() BOARD_USART_BASE->US_IER = ( AT91C_US_TXRDY | AT91C_US_RXRDY )
#define vInterruptOff() BOARD_USART_BASE->US_IDR = AT91C_US_TXRDY
/* Misc constants. */
#define serINVALID_QUEUE ( ( QueueHandle_t ) 0 )
#define serHANDLE ( ( xComPortHandle ) 1 )
#define serNO_BLOCK ( ( TickType_t ) 0 )
#define serNO_TIMEGUARD ( ( unsigned long ) 0 )
#define serNO_PERIPHERAL_B_SETUP ( ( unsigned long ) 0 )
/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static QueueHandle_t xRxedChars;
static QueueHandle_t xCharsForTx;
/*-----------------------------------------------------------*/
/* The interrupt service routine - called from the assembly entry point. */
void vSerialISR( void );
/*-----------------------------------------------------------*/
/*
* See the serial2.h header file.
*/
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
xComPortHandle xReturn = serHANDLE;
extern void ( vUART_ISR )( void );
const Pin xUSART_Pins[] = { BOARD_PIN_USART_RXD, BOARD_PIN_USART_TXD };
/* 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();
{
/* Enable the peripheral clock in the PMC. */
PMC_EnablePeripheral( BOARD_ID_USART );
/* Configure the USART. */
USART_Configure( BOARD_USART_BASE, AT91C_US_CHRL_8_BITS | AT91C_US_PAR_NONE | AT91C_US_NBSTOP_1_BIT, ulWantedBaud, configCPU_CLOCK_HZ );
/* Configure the interrupt. Note the pre-emption priority is set
in bits [8:15] of the priority value passed as the parameter. */
IRQ_ConfigureIT( BOARD_ID_USART, ( configMAX_SYSCALL_INTERRUPT_PRIORITY << 8 ), vSerialISR );
IRQ_EnableIT( BOARD_ID_USART );
/* Enable receiver & transmitter. */
USART_SetTransmitterEnabled( BOARD_USART_BASE, pdTRUE );
USART_SetReceiverEnabled( BOARD_USART_BASE, pdTRUE );
/* Configure IO for USART use. */
PIO_Configure( xUSART_Pins, PIO_LISTSIZE( xUSART_Pins ) );
}
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 )
{
/* Place the character in the queue of characters to be transmitted. */
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
{
return pdFAIL;
}
/* 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. */
vInterruptOn();
return pdPASS;
}
/*-----------------------------------------------------------*/
void vSerialClose( xComPortHandle xPort )
{
/* Not supported as not required by the demo application. */
}
/*-----------------------------------------------------------*/
void vSerialISR( void )
{
unsigned long ulStatus;
signed char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* What caused the interrupt? */
ulStatus = BOARD_USART_BASE->US_CSR &= BOARD_USART_BASE->US_IMR;
if( ulStatus & AT91C_US_TXRDY )
{
/* The interrupt was caused by the THR becoming empty. Are there any
more characters to transmit? */
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
{
/* A character was retrieved from the queue so can be sent to the
THR now. */
BOARD_USART_BASE->US_THR = cChar;
}
else
{
/* Queue empty, nothing to send so turn off the Tx interrupt. */
vInterruptOff();
}
}
if( ulStatus & AT91C_US_RXRDY )
{
/* The interrupt was caused by a character being received. Grab the
character from the RHR and place it in the queue or received
characters. */
cChar = BOARD_USART_BASE->US_RHR;
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
}
/* If a task was woken by either a character being received or a character
being transmitted then we may need to switch to another task. */
portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
}
|
