Started lab notes for labs 3 and 4.
This commit is contained in:
parent
fc1dbf88d9
commit
48bfa7b733
|
|
@ -3,3 +3,4 @@
|
|||
**/*.synctex.gz
|
||||
**/*.aux
|
||||
**/.vscode
|
||||
**/_minted*
|
||||
|
|
|
|||
Binary file not shown.
|
|
@ -0,0 +1,155 @@
|
|||
\documentclass[letterpaper]{article}
|
||||
\author{Jonathan Chan (15354146)}
|
||||
\title{PHYS 319\\Labs 3 and 4 Notes}
|
||||
|
||||
\usepackage{fullpage}
|
||||
\usepackage{minted}
|
||||
%{\renewcommand\fcolorbox[4][]{\textcolor{red}{\strut#4}}
|
||||
|
||||
\begin{document}
|
||||
\maketitle
|
||||
|
||||
To compile the C programs to .asm and .elf, I've modified my Makefile as below.
|
||||
\begin{minted}{makefile}
|
||||
SOURCES = $(wildcard *.c)
|
||||
EXEC = $(patsubst %.c, %.elf, $(SOURCES))
|
||||
DEVICE = msp430g2553
|
||||
INSTALL_DIR=$(HOME)/ti/msp430_gcc
|
||||
|
||||
GCC_DIR = $(INSTALL_DIR)/bin
|
||||
SUPPORT_FILE_DIRECTORY = $(INSTALL_DIR)/include
|
||||
|
||||
CC = $(GCC_DIR)/msp430-elf-gcc
|
||||
GDB = $(GCC_DIR)/msp430-elf-gdb
|
||||
|
||||
#O0 works, O1 works, O2 doesn't -Os works
|
||||
CFLAGS = -I $(SUPPORT_FILE_DIRECTORY) -mmcu=$(DEVICE) -Os -g
|
||||
LFLAGS = -L $(SUPPORT_FILE_DIRECTORY) -T $(DEVICE).ld
|
||||
|
||||
all: prog1 prog2 adc pwm
|
||||
|
||||
prog1: prog1.c
|
||||
$(CC) $(CFLAGS) $(LFLAGS) $? -o prog1.elf
|
||||
$(CC) $(CFLAGS) $(LFLAGS) $? -S -o prog1.asm
|
||||
prog2: prog2.c
|
||||
$(CC) $(CFLAGS) $(LFLAGS) $? -o prog2.elf
|
||||
$(CC) $(CFLAGS) $(LFLAGS) $? -S -o prog2.asm
|
||||
adc: adc.c
|
||||
$(CC) $(CFLAGS) $(LFLAGS) $? -o adc.elf
|
||||
$(CC) $(CFLAGS) $(LFLAGS) $? -S -o adc.asm
|
||||
pwm: pwm.c
|
||||
$(CC) $(CFLAGS) $(LFLAGS) $? -o pwm.elf
|
||||
$(CC) $(CFLAGS) $(LFLAGS) $? -S -o pwm.asm
|
||||
|
||||
debug: all
|
||||
$(GDB) ${EXEC}
|
||||
|
||||
clean:
|
||||
rm prog1.elf prog2.elf adc.elf pwm.elf prog1.asm prog2.asm adc.asm pwm.asm
|
||||
\end{minted}
|
||||
|
||||
\section{Program 1}
|
||||
Compiling from C, the produced Assembly file has a \textit{lot} of extra code, and appears to have been optimized differently. Below is the relevant section of the compiled .asm with some comments comparing lines to last lab's prog1.asm code.
|
||||
|
||||
\begin{minted}{gas}
|
||||
.LCFI0:
|
||||
.loc 1 21 0
|
||||
MOV.W #23168, &WDTCTL ; turn off watchdog
|
||||
.loc 1 22 0
|
||||
MOV.B #65, &P1DIR ; set output direction (P1.6 and P1.0 for LEDs)
|
||||
.loc 1 23 0
|
||||
MOV.B #1, &P1OUT ; set initial state (LED1 on)
|
||||
.LBB2:
|
||||
.loc 1 27 0
|
||||
MOV.W #-5536, R12 ; amount to decrement by (60000 shown as signed word)
|
||||
.L6:
|
||||
.LVL0:
|
||||
MOV.W R12, @R1 ; use R1 as working register to decrement (first loop)
|
||||
.L3:
|
||||
.loc 1 28 0
|
||||
MOV.W @R1, R13 ; use R13 as working register for this loop
|
||||
CMP.W #0, R13 { JEQ .L2 ; go to next countdown if this one has reached zero
|
||||
.loc 1 29 0
|
||||
ADD.W #-1, @R1 ; decrement counter
|
||||
BR #.L3 ; loop
|
||||
.L2:
|
||||
.LVL1:
|
||||
.loc 1 27 0
|
||||
MOV.W R12, @R1 ; reset R1 as working register to decrement (second loop)
|
||||
.L5:
|
||||
.loc 1 28 0
|
||||
MOV.W @R1, R13 ; use R13 as working register for this loop
|
||||
CMP.W #0, R13 { JEQ .L4 ; break if countdown has reached zero
|
||||
.loc 1 29 0
|
||||
ADD.W #-1, @R1 ; decrement counter
|
||||
BR #.L5 ; loop
|
||||
.L4:
|
||||
.LVL2:
|
||||
.LBE2:
|
||||
.loc 1 32 0 discriminator 1
|
||||
XOR.B #65, &P1OUT ; switch LEDs
|
||||
.loc 1 26 0 discriminator 1
|
||||
BR #.L6 ; loop from top of loops
|
||||
\end{minted}
|
||||
|
||||
\newpage
|
||||
This was generated using the following C code that doubles the count and thus halves the blinking rate.
|
||||
|
||||
\begin{minted}{c}
|
||||
#include <msp430.h>
|
||||
|
||||
void main(void) {
|
||||
volatile unsigned int count;
|
||||
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
|
||||
P1DIR = 0x41; // Set P1 output direction
|
||||
P1OUT = 0x01; // Set the output
|
||||
|
||||
while (1) { // Loop forever
|
||||
for (volatile unsigned char i = 0; i < 2; i++) { // decrement by 60000 twice
|
||||
count = 60000;
|
||||
while (count != 0) {
|
||||
count--; // decrement
|
||||
}
|
||||
}
|
||||
P1OUT = P1OUT ^ 0x41; // bitwise xor the output with 0x41
|
||||
}
|
||||
}
|
||||
\end{minted}
|
||||
|
||||
\section{Program 2}
|
||||
Below is the C code used to make the LEDs blink in the red--green--both--none pattern, using the same XOR trick described in the last lab notes.
|
||||
|
||||
\begin{minted}{c}
|
||||
#include <msp430.h>
|
||||
|
||||
volatile unsigned char stateChanger;
|
||||
|
||||
void main(void) {
|
||||
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
|
||||
P1DIR = 0xF7; // C does not have a convenient way of
|
||||
// representing numbers in binary; use hex instead
|
||||
P1OUT = 0x08; // LEDs off
|
||||
P1REN = 0x08; // enable resistor
|
||||
P1IE = 0x08; // Enable input at P1.3 as an interrupt
|
||||
stateChanger = 0x1; // 0x01 to toggle LED0; 0x40 to toggle LED1
|
||||
|
||||
_BIS_SR (LPM4_bits + GIE); // Turn on interrupts and go into the lowest
|
||||
// power mode (the program stops here)
|
||||
// Notice the strange format of the function, it is an "intrinsic"
|
||||
// ie. not part of C; it is specific to this chipset
|
||||
}
|
||||
|
||||
// Port 1 interrupt service routine
|
||||
void __attribute__ ((interrupt(PORT1_VECTOR))) PORT1_ISR(void) {
|
||||
P1OUT ^= stateChanger; // toggle the LEDS
|
||||
stateChanger ^= 0x40; // 0x01 -> 0x41 -> 0x01
|
||||
P1IFG &= ~0x08; // Clear P1.3 IFG. If you don't, it just happens again.
|
||||
}
|
||||
\end{minted}
|
||||
|
||||
\section{Analogue to Digital Conversion}
|
||||
|
||||
\section{Pulse Width Modulation}
|
||||
|
||||
\section{LED Dimmer}
|
||||
\end{document}
|
||||
Loading…
Reference in New Issue