I am basing an application off of this example and i am getting a lot of false positives on stall alerts which has been a headache. I am looking over this example and I am wondering why the global variables in the example are not volatile as they exist inside interrupts... I am not the best coder in C so it may be correct...
/*******************************************************************************
* Project Name: FW_Fan_Control_with_Alert
*
* Version: 1.0
*
* Theory of Operation:
*
* Fan Controller is configured into Automatic Firmware (CPU) fan control mode.
* Speed control algorithm is implemented in firmware using PID control
* algorithm.
* 2 Fans are supported (individual PWMs - no banks).
*
* 1st line of LCD displays Desired Speed and Actual Speed and PWM Duty Cycle
* of Fan 1
* 2nd line of LCD displays Actual Speed and PWM Duty Cycle of Fan 2
* SW1 decreases desired speed in RPM
* SW2 increases desired speed in RPM
* Fan stall/speed alert monitored - pulses GPIO, triggers interrupt which
* sets flag
*
********************************************************************************
* Copyright 2013-2015, Cypress Semiconductor Corporation. All rights reserved.
* This software is owned by Cypress Semiconductor Corporation and is protected
* by and subject to worldwide patent and copyright laws and treaties.
* Therefore, you may use this software only as provided in the license agreement
* accompanying the software package from which you obtained this software.
* CYPRESS AND ITS SUPPLIERS MAKE NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
* WITH REGARD TO THIS SOFTWARE, INCLUDING, BUT NOT LIMITED TO, NONINFRINGEMENT,
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*******************************************************************************/
#include <project.h>
#include <stdio.h>
#if defined (__GNUC__)
/* Add an explicit reference to the floating point printf library */
/* to allow the usage of floating point conversion specifiers. */
/* This is not linked in by default with the newlib-nano library. */
asm (".global _printf_float");
#endif
/***************************************
* Constants
***************************************/
#define MIN_RPM (1000u)
#define MAX_RPM (20000u)
#define INIT_RPM (4500u)
#define RPM_STEP (500u)
#define FAN_1 (1u)
#define FAN_2 (2u)
/***************************************
* Function Prototypes
***************************************/
CY_ISR_PROTO(AlertInt_Isr);
/***************************************
* Global variable declarations
***************************************/
uint16 stallStatus = 0u;
uint16 speedStatus = 0u;
/*******************************************************************************
* Function Name: main
********************************************************************************
*
* Summary:
* main() performs following functions:
* 1: Starts the components
* 2: Checks for Fan Stall and Speed Failure.
* 3: Displays Fan actual speeds when there are no errors.
* 4: Displays PWM duty cycles for each fan.
*
* Parameters:
* None.
*
* Return:
* None.
*
*******************************************************************************/
int main()
{
uint16 desiredSpeed = INIT_RPM;
uint8 fanNumber;
char string[6];
/* Enable interrupts to the CPU core */
CyGlobalIntEnable;
/* Start alert interrupt with a custom handler */
AlertInt_StartEx(&AlertInt_Isr);
/* Start components */
LCD_Start();
FanController_Start();
/* Set desired fan speed (fan number, rpm) */
FanController_SetDesiredSpeed(FAN_1, desiredSpeed);
FanController_SetDesiredSpeed(FAN_2, desiredSpeed);
FanController_EnableAlert();
LCD_Position(0u, 0u);
LCD_PrintNumber(desiredSpeed);
LCD_Position(1u, 0u);
LCD_PrintString("F/W");
while(1u)
{
/* If the tachometer block has read speeds of all fans in system,
* only then check speed/stall conditions.
*/
if(EOC_SR_Read())
{
for(fanNumber = FAN_1; fanNumber <= FAN_2; fanNumber++)
{
LCD_Position(fanNumber - 1u, 5u);
/* Check for Fan Stall and Speed Failure (flags set in AlertInt ISR) */
if(stallStatus & fanNumber)
{
LCD_PrintString("STALL");
stallStatus &= ~fanNumber;
}
else if(speedStatus & fanNumber)
{
LCD_PrintString("SPEED");
speedStatus &= ~fanNumber;
}
else
{
/* Display Fan actual speeds when there are no errors */
LCD_PrintNumber(FanController_GetActualSpeed(fanNumber));
LCD_PrintString(" ");
}
/* Display PWM duty cycles for each fan */
LCD_Position(fanNumber - 1u, 11u);
sprintf(string, "%4.1f", ((float)(FanController_GetDutyCycle(fanNumber))) / 100u);
LCD_PrintString(string);
LCD_PrintString("%");
}
}
/* Check for Button Press to Change Speed */
if((!SW1_Read()) || (!SW2_Read()))
{
/* Decrease Speed */
if(!SW1_Read())
{
if(desiredSpeed > MIN_RPM)
{
desiredSpeed -= RPM_STEP;
}
}
/* Increase Speed */
else
{
desiredSpeed += RPM_STEP;
if(desiredSpeed > MAX_RPM)
{
desiredSpeed = MAX_RPM;
}
}
FanController_SetDesiredSpeed(1u, desiredSpeed);
FanController_SetDesiredSpeed(2u, desiredSpeed);
/* Display Updated Desired Speed */
LCD_Position(0u, 0u);
LCD_PrintNumber(desiredSpeed);
LCD_PrintString(" ");
/* Switch Debounce */
CyDelay(250u);
}
}
}
/*******************************************************************************
* Function Name: AlertInt_Isr
********************************************************************************
* Summary:
* Informs main() routine about occured alerts.
*
* Parameters:
* None.
*
* Return:
* None.
*
*******************************************************************************/
CY_ISR(AlertInt_Isr)
{
uint8 alertStatus;
/* Determine alert source: stall or speed regulation failure (could be both) */
alertStatus = FanController_GetAlertSource();
/* If stall alert, determine which fan(s) */
if (alertStatus & FanController_STALL_ALERT)
{
stallStatus = FanController_GetFanStallStatus();
}
/* If speed regulation failure alert, determine which fan(s) */
if (alertStatus & FanController_SPEED_ALERT)
{
speedStatus = FanController_GetFanSpeedStatus();
}
}
/* [] END OF FILE */
