Testimonials

Recent comments from my mentees:

"Working with you was an insanely beneficial learning experience. Your approach to tackling problems is much more efficient than what I used to do." Amer

"I usually get confused by the details, you showed me how not to loose sight of the overall picture." Nansy

Programming the PIC microcontroller

Recently I helped my students with a PIC18F8722 microcontroller project. Hardware setup:

1. UNI-DS6 Development System + microboard with PIC18F8722 and seven segment display
2. PICkit 3 In-Circuit Debugger
3. Windows 10 PC + MPLAB X IDE + XC8 compiler

Notes:

• Pay attention on how the cable is connected to PICKit 3.
• Difference between PORT and LAT: The latch is the output latch onto which values are written. The port is the voltage at the actual pin… So in most situations, you will write to the latch and read from the port. When you're reading from LATx, you're reading what is in the Data Register, when you read from PORTx, you're reading the actual I/O pin value. PIC uses read-modify-write to write operations and this can be a problem, so they use this shadow register to avoid it.
• Setting timer and interrupt bits:

//Clear interrupts

INTCONbits.GIE = 0; //Global interrupt enable

INTCONbits.TMR0IE = 0; //Timer0 interrupt enable.

TMR0L = 0;    

TMR1 = 0;

//TIMER 0 (PIC18F8722)

INTCONbits.GIE = 1; //Global interrupt enable

INTCONbits.TMR0IE = 1; //Timer0 interrupt enable.

INTCONbits.TMR0IF = 0;

T0CONbits.T08BIT = 1;

T0CONbits.T0CS = 0; //internal clock selected

T0CONbits.PSA = 1; //prescaler is NOT assigned

T0CONbits.T0PS0 = 0;

T0CONbits.T0PS1 = 0;

T0CONbits.T0PS2 = 0;

T0CONbits.TMR0ON = 1;

//TIMER 1

T1CONbits.RD16 = 1;

T1CONbits.T1CKPS0 = 0;

T1CONbits.T1CKPS1 = 0;

T1CONbits.T1OSCEN = 0;

T1CONbits.TMR1CS = 0;

T1CONbits.TMR1ON = 1;

T1CONbits.T1RUN = 1;

• Using two timers with interrupt:

void __interrupt() isr(void) {

    if(TMR0IF) { //Timer 0 overflow

        TMR0IF = 0; //Clear Timer 0 interrupt flag

        TMR0 = 0; //Timer 0 counter

    }

    if(TMR1IF) { //Timer 1 overflow

        TMR1IF = 0; //Clear Timer 1 interrupt flag

        TMR1 = 30000; //Set counter so that overflow takes less time

    }

}

• Calculating timer overflow period:
• For 40MHz oscillator, use #pragma config OSC = HSPLL
• Frequency of instruction cyles = 40Mhz/4 = 10MHz → 1 instruction cyle = 0.1us
• 8 bit timer overflows every 2^8 instruction cycles = 256 * 0.1 = 25.6us
• 16 bit timer overflows every 2^16 instruction cycles = 6553.6us = 6.5536ms
• XC8 problem: Cannot use const int nTimer0_500ms = 19531; int maxTimer0 = nTimer0_500ms; XC8 displays message “error: (712) can't generate code for this expression” at the int maxTimer0 = nTimer0_500ms line. I had to use #define nTimer0_500ms (19531).
• cTimer0 > 2 * 19531 → we expected 1s delay but the board LEDs behaved strangely. When we used a prescaler of 1:2 (000), it worked as expected.
• Make Timer 1 faster by setting TMR1 to e.g. 30000 so that it start counting from TMR1 and number of counts until overflow would be 2^16 - TMR1.
• Finding a binary number corresponding to row: nb += 1 << iRow
• PORTA = 0b0011: Turn on first two LEDs in column A of board
• Turn on 4th bit of a number: nb |= 1<<4
• Turn off 4th bit of a number: nb &= ~(1<<4)
• You have to check button presses multiple times to give user time and to do debouncing.

Software related posts from my other blog

Here are the software related posts from my other blog, Şamil's Corner.

Bonus:

• Java
• Career advice
• Management
• Book reviews
• Favourite movies

How to fill a letter of intent/reference

Letters of intent or reference sometimes have a minimum word requirement. The best way to hit the word count is to give examples of which courses and projects you liked and why.

AI explanation problem

AI / machine learning is quite useful but not being able to see the justification of a particular classification outcome is quite annoying for me. As Mr. Tizhoosh puts it in Introduction to Digital Pathology:

After weeks of training of some sort of agent I can just tell you "yes" but I cannot tell you "why"... The pathologist writes a full scale report and he/she has to justify it.

See Explainable artificial intelligence.

Advanced Driver Assistance Systems (ADAS)

I recently bought and watched Udemy's Advanced Driver Assistance Systems (ADAS). It is a good beginner course to get an overview of concepts and challenges/steps to reach the goal of full self driving cars. It is especially useful if you plan on working in the smart/self-driving automotive industry.

Another good idea is to check out openpilot, which powers comma.ai. Here is a video of George Hotz showcasing openpilot.

Companies in Türkiye working on ADAS / autonomous driving:

• TOGG
• Ford Otosan

Touch typing

Touch typing (typing without looking at the keyboard) is an essential skill. Here is an intro video. Placement test. My current stats: 50 words per minute at 90% accuracy. Diary of a person learning to touch type.

As with any skill in life, the key is regular daily practice. "Hard work beats talent when talent doesn't work hard"