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/*
* FreeRTOS Kernel V10.4.0
* 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.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/* 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 warnigns. */
( 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 );
}
}
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