| /* | |
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| */ | |
| /* | |
| BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR USART1. | |
| ***Note*** This example uses queues to send each character into an interrupt | |
| service routine and out of an interrupt service routine individually. This | |
| is done to demonstrate queues being used in an interrupt, and to deliberately | |
| load the system to test the FreeRTOS port. It is *NOT* meant to be an | |
| example of an efficient implementation. An efficient implementation should | |
| use FIFO's or DMA if available, and only use FreeRTOS API functions when | |
| enough has been received to warrant a task being unblocked to process the | |
| data. | |
| */ | |
| /* Scheduler includes. */ | |
| #include "FreeRTOS.h" | |
| #include "queue.h" | |
| #include "semphr.h" | |
| #include "comtest2.h" | |
| /* Library includes. */ | |
| #include "asf.h" | |
| /* Demo application includes. */ | |
| #include "demo_serial.h" | |
| /*-----------------------------------------------------------*/ | |
| /* Misc defines. */ | |
| #define serINVALID_QUEUE ( ( QueueHandle_t ) 0 ) | |
| #define serNO_BLOCK ( ( TickType_t ) 0 ) | |
| #define serPMC_USART_ID ( BOARD_ID_USART ) | |
| /* The USART supported by this file. */ | |
| #define serUSART_PORT ( USART1 ) | |
| #define serUSART_IRQ ( USART1_IRQn ) | |
| /* Every bit in the interrupt mask. */ | |
| #define serMASK_ALL_INTERRUPTS ( 0xffffffffUL ) | |
| /*-----------------------------------------------------------*/ | |
| /* The queue used to hold received characters. */ | |
| static QueueHandle_t xRxedChars; | |
| static QueueHandle_t xCharsForTx; | |
| /*-----------------------------------------------------------*/ | |
| /* | |
| * See the serial.h header file. | |
| */ | |
| xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) | |
| { | |
| uint32_t ulChar; | |
| xComPortHandle xReturn; | |
| const sam_usart_opt_t xUSARTSettings = | |
| { | |
| ulWantedBaud, | |
| US_MR_CHRL_8_BIT, | |
| US_MR_PAR_NO, | |
| US_MR_NBSTOP_1_BIT, | |
| US_MR_CHMODE_NORMAL, | |
| 0 /* Only used in IrDA mode. */ | |
| }; | |
| /* Create the queues used to hold Rx/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 ) ) | |
| { | |
| /* Enable the peripheral clock in the PMC. */ | |
| pmc_enable_periph_clk( serPMC_USART_ID ); | |
| /* Configure USART in serial mode. */ | |
| usart_init_rs232( serUSART_PORT, &xUSARTSettings, sysclk_get_cpu_hz() ); | |
| /* Disable all the interrupts. */ | |
| usart_disable_interrupt( serUSART_PORT, serMASK_ALL_INTERRUPTS ); | |
| /* Enable the receiver and transmitter. */ | |
| usart_enable_tx( serUSART_PORT ); | |
| usart_enable_rx( serUSART_PORT ); | |
| /* Clear any characters before enabling interrupt. */ | |
| usart_getchar( serUSART_PORT, &ulChar ); | |
| /* Enable Rx end interrupt. */ | |
| usart_enable_interrupt( serUSART_PORT, US_IER_RXRDY ); | |
| /* Configure and enable interrupt of USART. */ | |
| NVIC_SetPriority( serUSART_IRQ, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY ); | |
| NVIC_EnableIRQ( serUSART_IRQ ); | |
| } | |
| 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 USART1. */ | |
| ( 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 ) | |
| { | |
| signed portBASE_TYPE xReturn; | |
| /* This simple example only supports one port. */ | |
| ( void ) pxPort; | |
| if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS ) | |
| { | |
| xReturn = pdPASS; | |
| usart_enable_interrupt( serUSART_PORT, US_IER_TXRDY ); | |
| } | |
| else | |
| { | |
| xReturn = pdFAIL; | |
| } | |
| return xReturn; | |
| } | |
| /*-----------------------------------------------------------*/ | |
| void vSerialClose( xComPortHandle xPort ) | |
| { | |
| /* Not supported as not required by the demo application. */ | |
| ( void ) xPort; | |
| } | |
| /*-----------------------------------------------------------*/ | |
| /* | |
| * It should be noted that the com test tasks (which use make use of this file) | |
| * are included to demonstrate queues being used to communicate between tasks | |
| * and interrupts, and to demonstrate a context switch being performed from | |
| * inside an interrupt service routine. The serial driver used here is *not* | |
| * intended to represent an efficient implementation. Real applications should | |
| * make use of the USARTS peripheral DMA channel (PDC). | |
| */ | |
| void USART1_Handler( void ) | |
| { | |
| portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; | |
| uint8_t ucChar; | |
| uint32_t ulChar; | |
| uint32_t ulUSARTStatus, ulUSARTMask; | |
| ulUSARTStatus = usart_get_status( serUSART_PORT ); | |
| ulUSARTMask = usart_get_interrupt_mask( serUSART_PORT ); | |
| ulUSARTStatus &= ulUSARTMask; | |
| if( ( ulUSARTStatus & US_CSR_TXRDY ) != 0UL ) | |
| { | |
| /* The interrupt was caused by the TX register becoming empty. Are | |
| there any more characters to transmit? */ | |
| if( xQueueReceiveFromISR( xCharsForTx, &ucChar, &xHigherPriorityTaskWoken ) == pdTRUE ) | |
| { | |
| /* A character was retrieved from the queue so can be sent to the | |
| USART now. */ | |
| usart_putchar( serUSART_PORT, ( uint32_t ) ucChar ); | |
| } | |
| else | |
| { | |
| usart_disable_interrupt( serUSART_PORT, US_IER_TXRDY ); | |
| } | |
| } | |
| if( ( ulUSARTStatus & US_CSR_RXRDY ) != 0UL ) | |
| { | |
| /* A character has been received on the USART, send it to the Rx | |
| handler task. */ | |
| usart_getchar( serUSART_PORT, &ulChar ); | |
| ucChar = ( uint8_t ) ( ulChar & 0xffUL ); | |
| xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken ); | |
| } | |
| /* If sending or receiving from a queue has caused a task to unblock, and | |
| the unblocked task has a priority equal to or higher than the currently | |
| running task (the task this ISR interrupted), then xHigherPriorityTaskWoken | |
| will have automatically been set to pdTRUE within the queue send or receive | |
| function. portEND_SWITCHING_ISR() will then ensure that this ISR returns | |
| directly to the higher priority unblocked task. */ | |
| portEND_SWITCHING_ISR( xHigherPriorityTaskWoken ); | |
| } | |