Davies Davies - 2 months ago 14
C++ Question

'accelerometer' and 'lcd' not declared in this scope

It's telling me that "accelerometer" and "lcd" were not declared in this scope when they're used in PIT0_IRQHandler. None of the solutions I've found online have worked as of yet so I figured I'd just post it up. I'm pretty new to this as well so feel free to point out any and every error included

#include <stdio.h>
#include "system.h"
#include "derivative.h"
#include "hardware.h"
#include "delay.h"
#include "lcd.h"
#include "i2c.h"
#include "level.h"
#include "mma845x.h"
#include "tone.h"
#include "accel.h"

/// LCD dimensions and centerpoint
#define LCD_WIDTH (LCD_X_MAX-LCD_X_MIN)
#define LCD_HEIGHT (LCD_Y_MAX-LCD_Y_MIN)
#define CENTRE_X ((LCD_X_MAX-LCD_X_MIN)/2)
#define CENTRE_Y ((LCD_Y_MAX-LCD_Y_MIN)/2)

#define BACKGROUND_COLOUR (RED)
#define FOREGROUND_COLOUR (WHITE)
#define CIRCLE_RADIUS (20)

using namespace USBDM;

void initialisePIT(int channel, uint32_t interval) {
// Enable clock to PIT
SIM->SCGC6 |= SIM_SCGC6_PIT_MASK;
// Enable PIT module
PIT->MCR = PIT_MCR_FRZ_MASK;
// Set reload value
PIT->CHANNEL[channel].LDVAL = interval-1;
// Enable this channel with interrupts
PIT->CHANNEL[channel].TCTRL = PIT_TCTRL_TEN_MASK|PIT_TCTRL_TIE_MASK;
// Enable PITn interrupts in NVIC
NVIC_EnableIRQ((IRQn_Type)(PIT0_IRQn+channel));
// Set arbitrary priority level
NVIC_SetPriority((IRQn_Type)(PIT0_IRQn+channel), 8);
}

void initialiseLCD(){
// Instantiate SPI interface class
Spi *spi = new Spi0();
// Instantiate LCD interface class
Lcd *lcd = new Lcd(spi);
// Clear Background and set to a preset (Set above) colour
lcd->clear(BACKGROUND_COLOUR);
// Draw crosshairs and initial circle on the screen
lcd->drawLine(LCD_WIDTH/2,LCD_WIDTH/2,0,LCD_HEIGHT,BLACK);
lcd->drawLine(0,LCD_WIDTH,LCD_HEIGHT/2,LCD_HEIGHT/2,BLACK);
lcd->drawCircle(CENTRE_X, CENTRE_Y, 20, WHITE);
}

void initialiseAccel()
{
I2c *i2c = new I2c0();
MMA845x *accelerometer = new MMA845x(i2c, MMA845x::ACCEL_2Gmode);
}

void PIT0_IRQHandler(void) {
int accelStatus;
int16_t accelX,accelY,accelZ;
accelerometer->readAccelerometerXYZ(&accelStatus, &accelX, &accelY, &accelZ);

lcd->clear(BACKGROUND_COLOUR);
lcd->drawCircle(accelX,accelY,20,WHITE);

// Clear the interrupt request from PIT
PIT->CHANNEL[0].TFLG = PIT_TFLG_TIF_MASK;
}

Answer

accelerometer is declared in initialiseAccel. It will go out of scope at the end of that function, and is not a known name in PIT0_IRQHandler. You should probably create a class to hold those variables and functions, or you'll have to use global variables (possibly in a namespace) to hold those values.

Comments