[修改] 增加freeRTOS

1. 版本FreeRTOSv202212.01，命名为kernel；

kernel/FreeRTOS/Demo/PIC24_MPLAB/lcd.c

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+/*
+ * FreeRTOS V202212.01
+ * Copyright (C) 2020 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.
+ *
+ * https://www.FreeRTOS.org
+ * https://github.com/FreeRTOS
+ *
+ */
+
+/* Scheduler includes. */
+#include "FreeRTOS.h"
+#include "task.h"
+#include "queue.h"
+
+/* Demo includes. */
+#include "lcd.h"
+
+/*
+ * The LCD is written to by more than one task so is controlled by this
+ * 'gatekeeper' task.  This is the only task that is actually permitted to
+ * access the LCD directly.  Other tasks wanting to display a message send
+ * the message to the gatekeeper.
+ */
+static void vLCDTask( void *pvParameters );
+
+/*
+ * Setup the peripherals required to communicate with the LCD.
+ */
+static void prvSetupLCD( void );
+
+/* 
+ * Move to the first (0) or second (1) row of the LCD. 
+ */
+static void prvLCDGotoRow( unsigned short usRow );
+
+/* 
+ * Write a string of text to the LCD. 
+ */
+static void prvLCDPutString( char *pcString );
+
+/* 
+ * Clear the LCD. 
+ */
+static void prvLCDClear( void );
+
+/*-----------------------------------------------------------*/
+
+/* Brief delay to permit the LCD to catch up with commands. */
+#define lcdSHORT_DELAY		3
+
+/* SFR that seems to be missing from the standard header files. */
+#define PMAEN				*( ( unsigned short * ) 0x60c )
+
+/* LCD commands. */
+#define lcdDEFAULT_FUNCTION	0x3c
+#define lcdDISPLAY_CONTROL	0x0c
+#define lcdCLEAR_DISPLAY	0x01
+#define lcdENTRY_MODE		0x06
+
+/* The length of the queue used to send messages to the LCD gatekeeper task. */
+#define lcdQUEUE_SIZE		3
+/*-----------------------------------------------------------*/
+
+/* The queue used to send messages to the LCD task. */
+QueueHandle_t xLCDQueue;
+
+
+/*-----------------------------------------------------------*/
+
+QueueHandle_t xStartLCDTask( void )
+{
+	/* Create the queue used by the LCD task.  Messages for display on the LCD
+	are received via this queue. */
+	xLCDQueue = xQueueCreate( lcdQUEUE_SIZE, sizeof( xLCDMessage ) );
+
+	/* Start the task that will write to the LCD.  The LCD hardware is
+	initialised from within the task itself so delays can be used. */
+	xTaskCreate( vLCDTask, "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );
+
+	return xLCDQueue;
+}
+/*-----------------------------------------------------------*/
+
+static void prvLCDGotoRow( unsigned short usRow )
+{
+	if( usRow == 0 )
+	{
+		PMADDR = 0x0000;
+		PMDIN1 = 0x02;
+	}
+	else
+	{
+		PMADDR = 0x0000;
+		PMDIN1 = 0xc0;
+	}
+
+	vTaskDelay( lcdSHORT_DELAY );
+}
+/*-----------------------------------------------------------*/
+
+static void prvLCDPutString( char *pcString )
+{
+	/* Write out each character with appropriate delay between each. */
+	while( *pcString )
+	{
+		PMADDR = 0x0001;
+		PMDIN1 = *pcString;
+		pcString++;
+		vTaskDelay( lcdSHORT_DELAY );
+	}
+}
+/*-----------------------------------------------------------*/
+
+static void prvLCDClear( void )
+{
+	/* Clear the display. */
+	PMADDR = 0x0000;
+	PMDIN1 = lcdCLEAR_DISPLAY;
+	vTaskDelay( lcdSHORT_DELAY );	
+}
+/*-----------------------------------------------------------*/
+
+static void prvSetupLCD( void )
+{
+	/* Setup the PMP. */
+	PMCON = 0x83BF;
+	PMMODE = 0x3FF;
+	PMAEN = 1;
+	PMADDR = 0x0000;
+	vTaskDelay( lcdSHORT_DELAY );
+
+	/* Set the default function. */
+	PMDIN1 = lcdDEFAULT_FUNCTION;
+	vTaskDelay( lcdSHORT_DELAY );
+
+	/* Set the display control. */
+	PMDIN1 = lcdDISPLAY_CONTROL;
+	vTaskDelay( lcdSHORT_DELAY );
+
+	/* Clear the display. */
+	PMDIN1 = lcdCLEAR_DISPLAY;
+	vTaskDelay( lcdSHORT_DELAY );
+
+	/* Set the entry mode. */
+	PMDIN1 = lcdENTRY_MODE;
+	vTaskDelay( lcdSHORT_DELAY );
+}
+/*-----------------------------------------------------------*/
+
+static void vLCDTask( void *pvParameters )
+{
+xLCDMessage xMessage;
+unsigned short usRow = 0;
+
+	/* Remove compiler warnings. */
+	( void ) pvParameters;
+
+	/* Initialise the hardware.  This uses delays so must not be called prior
+	to the scheduler being started. */
+	prvSetupLCD();
+
+	/* Welcome message. */
+	prvLCDPutString( "www.FreeRTOS.org" );
+
+	for( ;; )
+	{
+		/* Wait for a message to arrive that requires displaying. */
+		while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS );
+
+		/* Clear the current display value. */
+		prvLCDClear();
+
+		/* Switch rows each time so we can see that the display is still being
+		updated. */
+		prvLCDGotoRow( usRow & 0x01 );
+		usRow++;
+		prvLCDPutString( xMessage.pcMessage );
+
+		/* Delay the requested amount of time to ensure the text just written 
+		to the LCD is not overwritten. */
+		vTaskDelay( xMessage.xMinDisplayTime );		
+	}
+}
+
+
+
+