UT.6.01
UT.6.01x
Az UT.6.01x egy online kurzus, ami a Tiva C lauchpad-ről és a beágyazott rendszerekről szól.
A kurzust Jonathan Valvano és Ramesh Yerraballi tartja.
Ezen az oldalon a kurzusból idézett szöveg kiemelések, táblázatok és képek vannak, ezeket használom jegyzetnek.
C1 Bevezetés
Folyamatosan gyűjtöm az anyagokat és fordítom, ahogy lehet
C2 Alap fogalmak
Bináris számok és rendszerek
Hexadecimális számok
|
Hex Digit |
Decimal Value |
Binary Value |
|
0 |
0 |
0000 |
|
1 |
1 |
0001 |
|
2 |
2 |
0010 |
|
3 |
3 |
0011 |
|
4 |
4 |
0100 |
|
5 |
5 |
0101 |
|
6 |
6 |
0110 |
|
7 |
7 |
0111 |
|
8 |
8 |
1000 |
|
9 |
9 |
1001 |
|
A or a |
10 |
1010 |
|
B or b |
11 |
1011 |
|
C or c |
12 |
1100 |
|
D or d |
13 |
1101 |
|
E or e |
14 |
1110 |
|
F or f |
15 |
1111 |
Beágyazott rendszerek
Processzor típusok: x86 (ált. asztali gép), ARM.
"Az I/O az a ragasztó, amivel a processzor kapcsolódik a világhoz."
Tervezési szempontok: tesztelhetőség, haszon, energia igény, méret, megfelelő válasz megfelelő időben.
Human-computer interface (HCI) or man-machine interface (MMI).
Tipikus példa: multiméter.
Bevezetés a számítógépekhez
Neumann architecture
Számítógép = proceszor + RAM + ROM + IO.
Neumann architecture,
"A port is a physical connection between the computer and its outside world. Ports allow information to enter and exit the system."
"A bus is a collection of wires used to pass information between modules."
A busz vezetékek gyűjteménye, amit a modulok közti információ cserére használunk.
Harvard architecture
ARM®Cortex™-M processor. "separate data and instruction buses"
Külön adat, és utasítás buszok.
"The nested vectored interrupt controller (NVIC) manages interrupts, which are hardware-triggered software functions. "
A beágyazott irányítható megszakítás-vezérlő - NVIC
Fogalmak
A microprocessor is a small processor.
A microcomputer is a small computer that includes a processor, memory and I/O devices.
A microcontroller is a single chip computer.
IO portok
CPU regiszterek
ISA Instruction set architecture
MEMORY MAP LAYOUT
RAM (random access memory)
ROM (read only memory)
ROM-ok:
Static RAM (SRAM)
Programmable ROM (PROM) 10000 times slower RAM
Electrically erasable programmable ROM (EEPROM)
"In regular EEPROM, you can erase and program individual bytes. "
FLASH ROM
"Flash ROM is a popular type of EEPROM. Each flash bit requires only two MOSFET transistors. The input (gate) of one transistor is electrically isolated, so if we trap charge on this input, it will remain there for years."
"Each flash bit requires only two MOSFET transistors The input (gate) of one transistor is electrically isolated, so if we trap charge on this input, it will remain there for years. The other transistor is used to read the bit by sensing whether or not the other transistor has trapped charge."
"Flash ROM must be erased in large blocks. On many of Stellaris family of microcontrollers, we can erase the entire ROM or just a 1024-byte block."
"Because flash is smaller than regular EEPROM, most microcontrollers have a large flash into which we store the software. For all the systems in this class, we will store instructions and constants in flash ROM and place variables and temporary data in static RAM."
"Flash ROM is higher density because it requires few transistors compared to RAM."
Software
CortexM_InstructionSet.pdf Instruction Set Reference Manual https://courses.edx.org/c4x/UTAustinX/UT.6.01x/asset/CortexM_InstructionSet.pdf
CortexM4_TRM_r0p1.pdf Cortex-M4 Technical Reference Manual https://courses.edx.org/c4x/UTAustinX/UT.6.01x/asset/CortexM_InstructionSet.pdf
LaunchPadUsersManual.pdf LaunchPad Manual
tm4c123gh6pm.pdf Data Sheet for the TM4C123 microcontroller
C3 Elektronikai alapismeretek
Ohm törvény
R = V / I I = V / R
R = V / I
P = V * I Power = Voltage * Current
P = V2 / R Power = Voltage2 / Resistance P = I2 * R Power = Current2 * Resistance
Energia
Elemekre:
E (energia)= V (feszültség) * I (áramerősség) * time (idő)
E-> állandó ; V -> állandó, az idő vagy az I csökkentésével csökkenthetjük a felhasznált energiát.
C4 Digitális logikai műveletek
D Logikai műveletek
|
A |
B |
AND |
NAND |
OR |
NOR |
EOR |
Ex NOR |
|
0 |
0 |
0 |
1 |
0 |
1 |
0 |
1 |
|
0 |
1 |
0 |
1 |
1 |
0 |
1 |
0 |
|
1 |
0 |
0 |
1 |
1 |
0 |
1 |
0 |
|
1 |
1 |
1 |
0 |
1 |
0 |
0 |
1 |
|
Symbol |
A&B |
~(A&B) |
A|B |
~(A|B) |
A^B |
~(A^B) |
|
Boolean Algebra
|
A & B = B & A |
Commutative Law |
Large numbers reference
|
Value |
SI Decimal |
SI Decimal |
|
Value |
IEC Binary |
IEC Binary |
|
10001 |
k |
kilo- |
|
10241 |
Ki |
kibi- |
|
10002 |
M |
mega- |
|
10242 |
Mi |
mebi- |
|
10003 |
G |
giga- |
|
10243 |
Gi |
gibi- |
|
10004 |
T |
tera- |
|
10244 |
Ti |
tebi- |
|
10005 |
P |
peta- |
|
10245 |
Pi |
pebi- |
|
10006 |
E |
exa- |
|
10246 |
Ei |
exbi- |
|
10007 |
Z |
zetta- |
|
10247 |
Zi |
zebi- |
|
10008 |
Y |
yotta- |
|
10248 |
Yi |
yobi- |
C4 Beveztés a C-be
Háttér
A C nagyon népszerű nyelv (2013-ban a programok 18%), több programot írnak C-ben mint Javaban, PHP-ben, Python-ban vagy Perl-ben.
Szintén nagyon népszerű még Objective-C és a C++ is.
A C nagyon vas közeli, a beágyazott rendszerek pedig az I/O-kra (GPIO-kra) épülnek.
A C felépítése
|
Punctuation |
Meaning |
|
; |
End of statement |
|
: |
Defines a label |
|
, |
Separates elements of a list |
|
( ) |
Start and end of a parameter list |
|
{ } |
Start and stop of a compound statement |
|
[ ] |
Start and stop of a array index |
|
" " |
Start and stop of a string |
|
' ' |
Start and stop of a character constant |
Változók (variables)
|
Data type |
Precision |
Range |
|
unsigned char |
8-bit unsigned |
0 to +255 |
|
signed char |
8-bit signed |
-128 to +127 |
|
unsigned int |
compiler-dependent |
|
|
int |
compiler-dependent |
|
|
unsigned short |
16-bit unsigned |
0 to +65535 |
|
short |
16-bit signed |
-32768 to +32767 |
|
unsigned long |
unsigned 32-bit |
0 to 4294967295L |
|
long |
signed 32-bit |
-2147483648L to 2147483647L |
|
float |
32-bit float |
±10-38 to ±10+38 |
|
double |
64-bit float |
±10-308 to ±10+308 |
Műveletek, operátorok
|
Operation |
Meaning |
|
Operation |
Meaning |
|
= |
Assignment statement |
|
== |
Equal to comparison |
|
? |
Selection |
|
<= |
Less than or equal to |
|
< |
Less than |
|
>= |
Greater than or equal to |
|
> |
Greater than |
|
!= |
Not equal to |
|
! |
Logical not (true to false, false to true) |
|
<< |
Shift left |
|
~ |
1’s complement |
|
>> |
Shift right |
|
+ |
Addition |
|
++ |
Increment |
|
- |
Subtraction |
|
-- |
Decrement |
|
* |
Multiply or pointer reference |
|
&& |
Boolean and |
|
/ |
Divide |
|
|| |
Boolean or |
|
% |
Modulo, division remainder |
|
+= |
Add value to |
|
| |
Logical or |
|
-= |
Subtract value to |
|
& |
Logical and, or address of |
|
*= |
Multiply value to |
|
^ |
Logical exclusive or |
|
/= |
Divide value to |
|
. |
Used to access parts of a structure |
|
|= |
Or value to |
|
|
|
|
&= |
And value to |
|
|
|
|
^= |
Exclusive or value to |
|
|
|
|
<<= |
Shift value left |
|
|
|
|
>>= |
Shift value right |
|
|
|
|
%= |
Modulo divide value to |
|
|
|
|
-> |
Pointer to a structure |
|
Precedence |
Operators |
Associativity |
|
Highest |
() []. -> ++(postfix) --(postfix) |
Left to right |
|
|
++(prefix) --(prefix) ! ~ sizeof(type) +(unary) -(unary) &(address) *(dereference) |
Right to left |
|
|
* / % |
Left to right |
|
|
+ - |
Left to right |
|
|
<< >> |
Left to right |
|
|
< <= > >= |
Left to right |
|
|
== != |
Left to right |
|
|
& |
Left to right |
|
|
^ |
Left to right |
|
|
| |
Left to right |
|
|
&& |
Left to right |
|
|
|| |
Left to right |
|
|
? : |
Right to left |
|
|
= += -= *= /= %= <<= >>= |= &= ^= |
Right to left |
|
Lowest |
, |
Left to right |
Kulcsszavak
|
Keyword |
Meaning |
|
__asm |
Specify a function is written in assembly code (specific to ARM Keil™ uVision®) |
|
auto |
Specifies a variable as automatic (created on the stack) |
|
break |
Causes the program control structure to finish |
|
case |
One possibility within a switch statement |
|
char |
Defines a number with a precision of 8 bits |
|
const |
Defines parameter as constant in ROM, and defines a local parameter as fixed value |
|
continue |
Causes the program to go to beginning of loop |
|
default |
Used in switch statement for all other cases |
|
do |
Used for creating program loops |
|
double |
Specifies variable as double precision floating point |
|
else |
Alternative part of a conditional |
|
extern |
Defined in another module |
|
float |
Specifies variable as single precision floating point |
|
for |
Used for creating program loops |
|
goto |
Causes program to jump to specified location |
|
if |
Conditional control structure |
|
int |
Defines a number with a precision that will vary from compiler to compiler |
|
long |
Defines a number with a precision of 32 bits |
|
register |
Specifies how to implement a local |
|
return |
Leave function |
|
short |
Defines a number with a precision of 16 bits |
|
signed |
Specifies variable as signed (default) |
|
sizeof |
Built-in function returns the size of an object |
|
static |
Stored permanently in memory, accessed locally |
|
struct |
Used for creating data structures |
|
switch |
Complex conditional control structure |
|
typedef |
Used to create new data types |
|
unsigned |
Always greater than or equal to zero |
|
void |
Used in parameter list to mean no parameter |
|
volatile |
Can change implicitly outside the direct action of the software. |
|
while |
Used for creating program loops |
C6 Prortok
I/O Signals
UART Universal asynchronous receiver/transmitter SSI Synchronous serial interface I2C Inter-integrated circuit Timer Periodic interrupts, input capture, and output compare PWM Pulse width modulation ADC Analog to digital converter, measure analog signals Analog Comparator Compare two analog signals QEI Quadrature encoder interface USB Universal serial bus Ethernet High-speed network CAN Controller area network JTAG Joint Test Action Group
"Common Error: Even though it is possible to use the five JTAG pins as general I/O, debugging most microcontroller boards will be more stable if these five pins are left dedicated to the JTAG debugger."
A JTAG tüskéket soha nem szabad általános I/O -ként használni, mert ezeken történik a debugg.