2 FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 Richard Barry.
\r
4 This file is part of the FreeRTOS.org distribution.
\r
6 FreeRTOS.org is free software; you can redistribute it and/or modify it
\r
7 under the terms of the GNU General Public License (version 2) as published
\r
8 by the Free Software Foundation and modified by the FreeRTOS exception.
\r
10 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
\r
11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
\r
12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
\r
15 You should have received a copy of the GNU General Public License along
\r
16 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
\r
17 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
\r
19 A special exception to the GPL is included to allow you to distribute a
\r
20 combined work that includes FreeRTOS.org without being obliged to provide
\r
21 the source code for any proprietary components. See the licensing section
\r
22 of http://www.FreeRTOS.org for full details.
\r
25 ***************************************************************************
\r
27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
\r
29 * This is a concise, step by step, 'hands on' guide that describes both *
\r
30 * general multitasking concepts and FreeRTOS specifics. It presents and *
\r
31 * explains numerous examples that are written using the FreeRTOS API. *
\r
32 * Full source code for all the examples is provided in an accompanying *
\r
35 ***************************************************************************
\r
39 Please ensure to read the configuration and relevant port sections of the
\r
40 online documentation.
\r
42 http://www.FreeRTOS.org - Documentation, latest information, license and
\r
45 http://www.SafeRTOS.com - A version that is certified for use in safety
\r
48 http://www.OpenRTOS.com - Commercial support, development, porting,
\r
49 licensing and training services.
\r
53 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
\r
56 /* Standard includes. */
\r
59 /* Scheduler includes. */
\r
60 #include "FreeRTOS.h"
\r
63 /* Demo application includes. */
\r
66 /* Atmel library includes. */
\r
67 #include <usart/usart.h>
\r
68 #include <aic/aic.h>
\r
69 #include <pmc/pmc.h>
\r
71 /*-----------------------------------------------------------*/
\r
73 /* Location of the COM0 registers. */
\r
74 #define serCOM0 ( ( AT91PS_USART ) AT91C_BASE_US0 )
\r
76 /* Interrupt control macros. */
\r
77 #define serINTERRUPT_LEVEL ( 5 )
\r
78 #define vInterruptOn() serCOM0->US_IER = ( AT91C_US_TXRDY | AT91C_US_RXRDY )
\r
79 #define vInterruptOff() serCOM0->US_IDR = AT91C_US_TXRDY
\r
81 /* Misc constants. */
\r
82 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
\r
83 #define serHANDLE ( ( xComPortHandle ) 1 )
\r
84 #define serNO_BLOCK ( ( portTickType ) 0 )
\r
85 #define serNO_TIMEGUARD ( ( unsigned portLONG ) 0 )
\r
86 #define serNO_PERIPHERAL_B_SETUP ( ( unsigned portLONG ) 0 )
\r
89 /* Queues used to hold received characters, and characters waiting to be
\r
91 static xQueueHandle xRxedChars;
\r
92 static xQueueHandle xCharsForTx;
\r
94 /*-----------------------------------------------------------*/
\r
96 /* The interrupt service routine. */
\r
97 __arm void vSerialISR( void );
\r
99 /*-----------------------------------------------------------*/
\r
102 * See the serial2.h header file.
\r
104 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
\r
106 xComPortHandle xReturn = serHANDLE;
\r
108 /* Create the queues used to hold Rx and Tx characters. */
\r
109 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
\r
110 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
\r
112 /* If the queues were created correctly then setup the serial port
\r
114 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
\r
116 PMC_EnablePeripheral( AT91C_ID_US0 );
\r
117 portENTER_CRITICAL();
\r
119 USART_Configure( serCOM0, ( AT91C_US_CHRL_8_BITS | AT91C_US_PAR_NONE ), ulWantedBaud, configCPU_CLOCK_HZ );
\r
121 /* Enable Rx and Tx. */
\r
122 USART_SetTransmitterEnabled( serCOM0, pdTRUE );
\r
123 USART_SetReceiverEnabled( serCOM0, pdTRUE );
\r
125 /* Enable the Rx interrupts. The Tx interrupts are not enabled
\r
126 until there are characters to be transmitted. */
\r
127 serCOM0->US_IER = AT91C_US_RXRDY;
\r
129 /* Enable the interrupts in the AIC. */
\r
130 AIC_ConfigureIT( AT91C_ID_US0, AT91C_AIC_PRIOR_LOWEST, ( void (*)( void ) ) vSerialISR );
\r
131 AIC_EnableIT( AT91C_ID_US0 );
\r
133 portEXIT_CRITICAL();
\r
137 xReturn = ( xComPortHandle ) 0;
\r
140 /* This demo file only supports a single port but we have to return
\r
141 something to comply with the standard demo header file. */
\r
144 /*-----------------------------------------------------------*/
\r
146 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
\r
148 /* The port handle is not required as this driver only supports one port. */
\r
151 /* Get the next character from the buffer. Return false if no characters
\r
152 are available, or arrive before xBlockTime expires. */
\r
153 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
\r
162 /*-----------------------------------------------------------*/
\r
164 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
\r
166 signed portCHAR *pxNext;
\r
168 /* A couple of parameters that this port does not use. */
\r
169 ( void ) usStringLength;
\r
172 /* NOTE: This implementation does not handle the queue being full as no
\r
173 block time is used! */
\r
175 /* The port handle is not required as this driver only supports UART0. */
\r
178 /* Send each character in the string, one at a time. */
\r
179 pxNext = ( signed portCHAR * ) pcString;
\r
182 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
\r
186 /*-----------------------------------------------------------*/
\r
188 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
\r
190 /* Just to remove compiler warning. */
\r
193 /* Place the character in the queue of characters to be transmitted. */
\r
194 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
\r
199 /* Turn on the Tx interrupt so the ISR will remove the character from the
\r
200 queue and send it. This does not need to be in a critical section as
\r
201 if the interrupt has already removed the character the next interrupt
\r
202 will simply turn off the Tx interrupt again. */
\r
207 /*-----------------------------------------------------------*/
\r
209 void vSerialClose( xComPortHandle xPort )
\r
211 /* Not supported as not required by the demo application. */
\r
214 /*-----------------------------------------------------------*/
\r
216 /* Serial port ISR. This can cause a context switch so is not defined as a
\r
217 standard ISR using the __irq keyword. Instead a wrapper function is defined
\r
218 within serialISR.s79 which in turn calls this function. See the port
\r
219 documentation on the FreeRTOS.org website for more information. */
\r
220 __arm void vSerialISR( void )
\r
222 unsigned portLONG ulStatus;
\r
223 signed portCHAR cChar;
\r
224 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
\r
226 /* What caused the interrupt? */
\r
227 ulStatus = serCOM0->US_CSR &= serCOM0->US_IMR;
\r
229 if( ulStatus & AT91C_US_TXRDY )
\r
231 /* The interrupt was caused by the THR becoming empty. Are there any
\r
232 more characters to transmit? */
\r
233 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
\r
235 /* A character was retrieved from the queue so can be sent to the
\r
237 serCOM0->US_THR = cChar;
\r
241 /* Queue empty, nothing to send so turn off the Tx interrupt. */
\r
246 if( ulStatus & AT91C_US_RXRDY )
\r
248 /* The interrupt was caused by a character being received. Grab the
\r
249 character from the RHR and place it in the queue or received
\r
251 cChar = serCOM0->US_RHR;
\r
252 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
\r
255 /* If a task was woken by either a character being received or a character
\r
256 being transmitted then we may need to switch to another task. */
\r
257 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
\r
259 /* End the interrupt in the AIC. */
\r
260 AT91C_BASE_AIC->AIC_EOICR = 0;
\r