Proteus presenting Stack underflow[STKUNF set, zero returned] when compiled - Page 1
Forum section: electronics / general

author: pjthedewg
author_rank: Newbie
timestamp: February 27, 2016, 10:08:42 am
content: The schematic is attached. The code, using c and the xc8 compiler for the pic18f46k22. I'm making a traffic light controller for 4 different lights. i set the delay to just 100ms temporarily. i'll fix that later and set it to loop so i get 5-15 second delay.Code:/** File: main.c* Author: IBRAHIM LABS* EMAIL: Ibrahimlabs@gmail.com** Website: http://www.ibrahimlabs.com/** Created on March 16, 2014, 8:05 PM*///#include <pic18f46k22>#include <xc.h>#define _XTAL_FREQ 1000000UL // 10MHz// CONFIG// CONFIG1H#pragma config FOSC = INTIO7 // Oscillator Selection bits (Internal oscillator block, CLKOUT function on OSC2)#pragma config PLLCFG = OFF // 4X PLL Enable (Oscillator used directly)#pragma config PRICLKEN = OFF // Primary clock enable bit (Primary clock can be disabled by software)#pragma config FCMEN = OFF // Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor disabled)#pragma config IESO = OFF // Internal/External Oscillator Switchover bit (Oscillator Switchover mode disabled)// CONFIG2L#pragma config PWRTEN = OFF // Power-up Timer Enable bit (Power up timer disabled)#pragma config BOREN = SBORDIS // Brown-out Reset Enable bits (Brown-out Reset enabled in hardware only (SBOREN is disabled))#pragma config BORV = 190 // Brown Out Reset Voltage bits (VBOR set to 1.90 V nominal)// CONFIG2H#pragma config WDTEN = OFF // Watchdog Timer Enable bits (Watch dog timer is always disabled. SWDTEN has no effect.)#pragma config WDTPS = 32768 // Watchdog Timer Postscale Select bits (1:32768)// CONFIG3H#pragma config CCP2MX = PORTC1 // CCP2 MUX bit (CCP2 input/output is multiplexed with RC1)#pragma config PBADEN = ON // PORTB A/D Enable bit (PORTB<5:0> pins are configured as analog input channels on Reset)#pragma config CCP3MX = PORTB5 // P3A/CCP3 Mux bit (P3A/CCP3 input/output is multiplexed with RB5)#pragma config HFOFST = ON // HFINTOSC Fast Start-up (HFINTOSC output and ready status are not delayed by the oscillator stable status)#pragma config T3CMX = PORTC0 // Timer3 Clock input mux bit (T3CKI is on RC0)#pragma config P2BMX = PORTD2 // ECCP2 B output mux bit (P2B is on RD2)#pragma config MCLRE = EXTMCLR // MCLR Pin Enable bit (MCLR pin enabled, RE3 input pin disabled)// CONFIG4L#pragma config STVREN = ON // Stack Full/Underflow Reset Enable bit (Stack full/underflow will cause Reset)#pragma config LVP = ON // Single-Supply ICSP Enable bit (Single-Supply ICSP enabled if MCLRE is also 1)#pragma config XINST = OFF // Extended Instruction Set Enable bit (Instruction set extension and Indexed Addressing mode disabled (Legacy mode))// CONFIG5L#pragma config CP0 = OFF // Code Protection Block 0 (Block 0 (000800-003FFFh) not code-protected)#pragma config CP1 = OFF // Code Protection Block 1 (Block 1 (004000-007FFFh) not code-protected)#pragma config CP2 = OFF // Code Protection Block 2 (Block 2 (008000-00BFFFh) not code-protected)#pragma config CP3 = OFF // Code Protection Block 3 (Block 3 (00C000-00FFFFh) not code-protected)// CONFIG5H#pragma config CPB = OFF // Boot Block Code Protection bit (Boot block (000000-0007FFh) not code-protected)#pragma config CPD = OFF // Data EEPROM Code Protection bit (Data EEPROM not code-protected)// CONFIG6L#pragma config WRT0 = OFF // Write Protection Block 0 (Block 0 (000800-003FFFh) not write-protected)#pragma config WRT1 = OFF // Write Protection Block 1 (Block 1 (004000-007FFFh) not write-protected)#pragma config WRT2 = OFF // Write Protection Block 2 (Block 2 (008000-00BFFFh) not write-protected)#pragma config WRT3 = OFF // Write Protection Block 3 (Block 3 (00C000-00FFFFh) not write-protected)// CONFIG6H#pragma config WRTC = OFF // Configuration Register Write Protection bit (Configuration registers (300000-3000FFh) not write-protected)#pragma config WRTB = OFF // Boot Block Write Protection bit (Boot Block (000000-0007FFh) not write-protected)#pragma config WRTD = OFF // Data EEPROM Write Protection bit (Data EEPROM not write-protected)// CONFIG7L#pragma config EBTR0 = OFF // Table Read Protection Block 0 (Block 0 (000800-003FFFh) not protected from table reads executed in other blocks)#pragma config EBTR1 = OFF // Table Read Protection Block 1 (Block 1 (004000-007FFFh) not protected from table reads executed in other blocks)#pragma config EBTR2 = OFF // Table Read Protection Block 2 (Block 2 (008000-00BFFFh) not protected from table reads executed in other blocks)#pragma config EBTR3 = OFF // Table Read Protection Block 3 (Block 3 (00C000-00FFFFh) not protected from table reads executed in other blocks)// CONFIG7H#pragma config EBTRB = OFF // Boot Block Table Read Protection bit (Boot Block (000000-0007FFh) not protected from table reads executed in other blocks)/***/#define G1 PORTBbits.RB0#define Y1 PORTBbits.RB1#define R1 PORTBbits.RB2#define G2 PORTBbits.RB3#define Y2 PORTBbits.RB4#define R2 PORTBbits.RB5#define G3 PORTCbits.RC0#define Y3 PORTCbits.RC1#define R3 PORTCbits.RC2#define G4 PORTCbits.RC3#define Y4 PORTCbits.RC4#define R4 PORTCbits.RC5#define start PORTAbits.RA4/*void delay_100ms(unsigned char n){}*/int main() {while(1){G1 = 1;R2 = 1;R3 = 1;R4 = 1;G2, G3, G4, Y1, Y2, Y3, Y4, R1 = 0;__delay_ms(100);Y1 = 1;Y2 = 1;R3 = 1;R4 = 1;G2, G3, G4, G1, R2, Y3, Y4, R1 = 0;__delay_ms(100);G2 = 1;R1 = 1;R3 = 1;R4 = 1;G1, G3, G4, Y1, Y2, Y3, Y4, R2 = 0;__delay_ms(100);Y3 = 1;Y2 = 1;R1 = 1;R4 = 1;G2, G3, G4, G1, Y1, R3, Y4, R2 = 0;__delay_ms(100);G3 = 1;R2 = 1;R1 = 1;R4 = 1;G2, G1, G4, Y1, Y2, Y3, Y4, R3 = 0;__delay_ms(100);Y3 = 1;Y4 = 1;R1 = 1;R2 = 1;G2, G3, G4, G1, Y2, Y1, R3, R4 = 0;__delay_ms(100);G4 = 1;R2 = 1;R3 = 1;R1 = 1;G2, G3, G1, Y1, Y2, Y3, Y4, R4 = 0;__delay_ms(100);Y1 = 1;Y4 = 1;R3 = 1;R2 = 1;G2, G3, G4, G1, Y2, Y3, R4, R1 = 0;__delay_ms(100);}return 0;}

author: newbrain
author_rank: Super Contributor
timestamp: February 27, 2016, 10:48:48 am
content: Quote from: pjthedewg on February 27, 2016, 10:08:42 amI cannot see any evident reason for a stack underflow, but I haven't ever touched a PIC, so my analysis is limited fromint main()to the closing brace.But I'm quite sure of one thing: the above quoted assignment is not doing what you hope it would.The comma operator in C evaluates then discards its first operand, then returns the result of the evaluation of the second operand.Also, it has left to right associativity and inserts a sequence point, completing the side effects of the first operand evaluation before evaluating the second one.This means that G1 is evaluated and discarded, then G3 and so on, until finally R2 = 0 is: apart from R2, all the other variable will keep their original values.

author: wraper
author_rank: Unknown
timestamp: February 27, 2016, 11:05:50 am
content: Don't rely on Proteus MCU emulation. It is very buggy, if something does not run properly in Proteus, very likely it will run without an issue on the real MCU.