UT.6.01

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A lap korábbi változatát látod, amilyen Balintadmin (vitalap | szerkesztései) 2014. március 19., 09:37-kor történt szerkesztése után volt. (→‎SysTick timer)
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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.



RAM-ROM memory

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."

IO portok

CPU regiszterek

UTx 6 02 ARM CortexM3 registers image013.gif
















Memory Map Layout

Part number

RAM

Flash

I/O

I/O modules

LM3S811

8

64

32

PWM

LM3S1968

64

256

52

PWM

LM3S2965

64

256

56

PWM, CAN

LM3S3748

64

128

61

PWM, DMA, USB

LM3S6965

64

256

42

PWM, Ethernet

LM3S8962

64

256

42

PWM, CAN, Ethernet, IEEE1588

LM4F110B2QR

12

32

43

floating point, CAN, DMA

LM4F120H5QR

32

256

43

floating point, CAN, DMA, USB

TM4C123GH6PM

32

256

43

floating point, CAN, DMA, USB, PWM

 

KiB

KiB

pins

 

ISA Instruction set architecture

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
A | B = B | A
(A & B) & C = A & (B & C)
(A | B) | C = A | (B | C)
(A | B) & C = (A & C) | (B & C)
(A & B) | C = (A | C) & (B | C)
A & 0 = 0
A | 0 = A
A & 1 = A
A | 1 = 1
A | A = A
A | (~A) = 1
A & A = A
A & (~A) = 0
~(~A) = A
~(A | B) = (~A) & (~B)
~(A & B) = (~A) | (~B)

Commutative Law
Commutative Law
Associative Law
Associative Law
Distributive Law
Distributive Law
Identity of 0
Identity of 0
Identity of 1
Identity of 1
Property of OR
Property of OR
Property of AND
Property of AND
Inverse
De Morgan’s Theorem
De Morgan’s Theorem

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.


I/O Pins


UTx 60 2 Cortex M3 MCUs c6-image001.gif


IO

Ain

0

1

2

3

4

5

6

7

8

9

14

PA0

 

Port

U0Rx

 

 

 

 

 

 

CAN1Rx

 

 

PA1

 

Port

U0Tx

 

 

 

 

 

 

CAN1Tx

 

 

PA2

 

Port

 

SSI0Clk

 

 

 

 

 

 

 

 

PA3

 

Port

 

SSI0Fss

 

 

 

 

 

 

 

 

PA4

 

Port

 

SSI0Rx

 

 

 

 

 

 

 

 

PA5

 

Port

 

SSI0Tx

 

 

 

 

 

 

 

 

PA6

 

Port

 

 

I2C1SCL

 

M1PWM2

 

 

 

 

 

PA7

 

Port

 

 

I2C1SDA

 

M1PWM3

 

 

 

 

 

PB0

 

Port

U1Rx

 

 

 

 

 

T2CCP0

 

 

 

PB1

 

Port

U1Tx

 

 

 

 

 

T2CCP1

 

 

 

PB2

 

Port

 

 

I2C0SCL

 

 

 

T3CCP0

 

 

 

PB3

 

Port

 

 

I2C0SDA

 

 

 

T3CCP1

 

 

 

PB4

Ain10

Port

 

SSI2Clk

 

M0PWM2

 

 

T1CCP0

CAN0Rx

 

 

PB5

Ain11

Port

 

SSI2Fss

 

M0PWM3

 

 

T1CCP1

CAN0Tx

 

 

PB6

 

Port

 

SSI2Rx

 

M0PWM0

 

 

T0CCP0

 

 

 

PB7

 

Port

 

SSI2Tx

 

M0PWM1

 

 

T0CCP1

 

 

 

PC4

C1-

Port

U4Rx

U1Rx

 

M0PWM6

 

IDX1

WT0CCP0

U1RTS

 

 

PC5

C1+

Port

U4Tx

U1Tx

 

M0PWM7

 

PhA1

WT0CCP1

U1CTS

 

 

PC6

C0+

Port

U3Rx

 

 

 

 

PhB1

WT1CCP0

USB0epen

 

 

PC7

C0-

Port

U3Tx

 

 

 

 

 

WT1CCP1

USB0pflt

 

 

PD0

Ain7

Port

SSI3Clk

SSI1Clk

I2C3SCL

M0PWM6

M1PWM0

 

WT2CCP0

 

 

 

PD1

Ain6

Port

SSI3Fss

SSI1Fss

I2C3SDA

M0PWM7

M1PWM1

 

WT2CCP1

 

 

 

PD2

Ain5

Port

SSI3Rx

SSI1Rx

 

M0Fault0

 

 

WT3CCP0

USB0epen

 

 

PD3

Ain4

Port

SSI3Tx

SSI1Tx

 

 

 

IDX0

WT3CCP1

USB0pflt

 

 

PD4

USB0DM

Port

U6Rx

 

 

 

 

 

WT4CCP0

 

 

 

PD5

USB0DP

Port

U6Tx

 

 

 

 

 

WT4CCP1

 

 

 

PD6

 

Port

U2Rx

 

 

M0Fault0

 

PhA0

WT5CCP0

 

 

 

PD7

 

Port

U2Tx

 

 

 

 

PhB0

WT5CCP1

NMI

 

 

PE0

Ain3

Port

U7Rx

 

 

 

 

 

 

 

 

 

PE1

Ain2

Port

U7Tx

 

 

 

 

 

 

 

 

 

PE2

Ain1

Port

 

 

 

 

 

 

 

 

 

 

PE3

Ain0

Port

 

 

 

 

 

 

 

 

 

 

PE4

Ain9

Port

U5Rx

 

I2C2SCL

M0PWM4

M1PWM2

 

 

CAN0Rx

 

 

PE5

Ain8

Port

U5Tx

 

I2C2SDA

M0PWM5

M1PWM3

 

 

CAN0Tx

 

 

PF0

 

Port

U1RTS

SSI1Rx

CAN0Rx

 

M1PWM4

PhA0

T0CCP0

NMI

C0o

 

PF1

 

Port

U1CTS

SSI1Tx

 

 

M1PWM5

PhB0

T0CCP1

 

C1o

TRD1

PF2

 

Port

 

SSI1Clk

 

M0Fault0

M1PWM6

 

T1CCP0

 

 

TRD0

PF3

 

Port

 

SSI1Fss

CAN0Tx

 

M1PWM7

 

T1CCP1

 

 

TRCLK

PF4

 

Port

 

 

 

 

M1Fault0

IDX0

T2CCP0

USB0epen

 

 

I/O Registers

"A DIR bit of 0 means input and 1 means output."

"Common Error: You will get a bus fault if you access a port without enabling its clock."


  • DIR 0 means input and 1 means output
  • PCTL select regular digital function.
  • LOCK unlock the port; Only PC3-0, PD7, and PF0 on the TM4C need to be unlocked
  • AMSEL analog functionality
  • AFSEL alternative function
  • PUR internal pull-up resistor

Registers

Address

7

6

5

4

3

2

1

0

Name

$400F.E108

--

--

GPIOF

GPIOE

GPIOD

GPIOC

GPIOB

GPIOA

SYSCTL_RCGC2_R

$4000.43FC

DATA

DATA

DATA

DATA

DATA

DATA

DATA

DATA

GPIO_PORTA_DATA_R

$4000.4400

DIR

DIR

DIR

DIR

DIR

DIR

DIR

DIR

GPIO_PORTA_DIR_R

$4000.4420

SEL

SEL

SEL

SEL

SEL

SEL

SEL

SEL

GPIO_PORTA_AFSEL_R

$4000.4510

PUE

PUE

PUE

PUE

PUE

PUE

PUE

PUE

GPIO_PORTA_PUR_R

$4000.451C

DEN

DEN

DEN

DEN

DEN

DEN

DEN

DEN

GPIO_PORTA_DEN_R

$4000.4524

1

1

1

1

1

1

1

1

GPIO_PORTA_CR_R

$4000.4528

0

0

0

0

0

0

0

0

GPIO_PORTA_AMSEL_R

$4000.53FC

DATA

DATA

DATA

DATA

DATA

DATA

DATA

DATA

GPIO_PORTB_DATA_R

$4000.5400

DIR

DIR

DIR

DIR

DIR

DIR

DIR

DIR

GPIO_PORTB_DIR_R

$4000.5420

SEL

SEL

SEL

SEL

SEL

SEL

SEL

SEL

GPIO_PORTB_AFSEL_R

$4000.5510

PUE

PUE

PUE

PUE

PUE

PUE

PUE

PUE

GPIO_PORTB_PUR_R

$4000.551C

DEN

DEN

DEN

DEN

DEN

DEN

DEN

DEN

GPIO_PORTB_DEN_R

$4000.5524

1

1

1

1

1

1

1

1

GPIO_PORTB_CR_R

$4000.5528

0

0

AMSEL

AMSEL

0

0

0

0

GPIO_PORTB_AMSEL_R

$4000.63FC

DATA

DATA

DATA

DATA

JTAG

JTAG

JTAG

JTAG

GPIO_PORTC_DATA_R

$4000.6400

DIR

DIR

DIR

DIR

JTAG

JTAG

JTAG

JTAG

GPIO_PORTC_DIR_R

$4000.6420

SEL

SEL

SEL

SEL

JTAG

JTAG

JTAG

JTAG

GPIO_PORTC_AFSEL_R

$4000.6510

PUE

PUE

PUE

PUE

JTAG

JTAG

JTAG

JTAG

GPIO_PORTC_PUR_R

$4000.651C

DEN

DEN

DEN

DEN

JTAG

JTAG

JTAG

JTAG

GPIO_PORTC_DEN_R

$4000.6524

1

1

1

1

JTAG

JTAG

JTAG

JTAG

GPIO_PORTC_CR_R

$4000.6528

AMSEL

AMSEL

AMSEL

AMSEL

JTAG

JTAG

JTAG

JTAG

GPIO_PORTC_AMSEL_R

$4000.73FC

DATA

DATA

DATA

DATA

DATA

DATA

DATA

DATA

GPIO_PORTD_DATA_R

$4000.7400

DIR

DIR

DIR

DIR

DIR

DIR

DIR

DIR

GPIO_PORTD_DIR_R

$4000.7420

SEL

SEL

SEL

SEL

SEL

SEL

SEL

SEL

GPIO_PORTD_AFSEL_R

$4000.7510

PUE

PUE

PUE

PUE

PUE

PUE

PUE

PUE

GPIO_PORTD_PUR_R

$4000.751C

DEN

DEN

DEN

DEN

DEN

DEN

DEN

DEN

GPIO_PORTD_DEN_R

$4000.7524

CR

1

1

1

1

1

1

1

GPIO_PORTD_CR_R

$4000.7528

0

0

AMSEL

AMSEL

AMSEL

AMSEL

AMSEL

AMSEL

GPIO_PORTD_AMSEL_R

$4002.43FC

 

 

DATA

DATA

DATA

DATA

DATA

DATA

GPIO_PORTE_DATA_R

$4002.4400

 

 

DIR

DIR

DIR

DIR

DIR

DIR

GPIO_PORTE_DIR_R

$4002.4420

 

 

SEL

SEL

SEL

SEL

SEL

SEL

GPIO_PORTE_AFSEL_R

$4002.4510

 

 

PUE

PUE

PUE

PUE

PUE

PUE

GPIO_PORTE_PUR_R

$4002.451C

 

 

DEN

DEN

DEN

DEN

DEN

DEN

GPIO_PORTE_DEN_R

$4002.4524

 

 

1

1

1

1

1

1

GPIO_PORTE_CR_R

$4002.4528

 

 

AMSEL

AMSEL

AMSEL

AMSEL

AMSEL

AMSEL

GPIO_PORTE_AMSEL_R

$4002.53FC

 

 

 

DATA

DATA

DATA

DATA

DATA

GPIO_PORTF_DATA_R

$4002.5400

 

 

 

DIR

DIR

DIR

DIR

DIR

GPIO_PORTF_DIR_R

$4002.5420

 

 

 

SEL

SEL

SEL

SEL

SEL

GPIO_PORTF_AFSEL_R

$4002.5510

 

 

 

PUE

PUE

PUE

PUE

PUE

GPIO_PORTF_PUR_R

$4002.551C

 

 

 

DEN

DEN

DEN

DEN

DEN

GPIO_PORTF_DEN_R

$4002.5524

 

 

 

1

1

1

1

CR

GPIO_PORTF_CR_R

$4002.5528

 

 

 

0

0

0

0

0

GPIO_PORTF_AMSEL_R

 

 

 

 

 

 

 

 

 

 

 

31-28

27-24

23-20

19-16

15-12

11-8

7-4

3-0

 

$4000.452C

PMC7

PMC6

PMC5

PMC4

PMC3

PMC2

PMC1

PMC0

GPIO_PORTA_PCTL_R

$4000.552C

PMC7

PMC6

PMC5

PMC4

PMC3

PMC2

PMC1

PMC0

GPIO_PORTB_PCTL_R

$4000.652C

PMC7

PMC6

PMC5

PMC4

0x1

0x1

0x1

0x1

GPIO_PORTC_PCTL_R

$4000.752C

PMC7

PMC6

PMC5

PMC4

PMC3

PMC2

PMC1

PMC0

GPIO_PORTD_PCTL_R

$4002.452C

 

 

PMC5

PMC4

PMC3

PMC2

PMC1

PMC0

GPIO_PORTE_PCTL_R

$4002.552C

 

 

 

PMC4

PMC3

PMC2

PMC1

PMC0

GPIO_PORTF_PCTL_R

$4000.6520

LOCK (write 0x4C4F434B to unlock, other locks) (reads 1 if locked, 0 if unlocked)

GPIO_PORTC_LOCK_R

$4000.7520

LOCK (write 0x4C4F434B to unlock, other locks) (reads 1 if locked, 0 if unlocked)

GPIO_PORTD_LOCK_R

$4002.5520

LOCK (write 0x4C4F434B to unlock, other locks) (reads 1 if locked, 0 if unlocked)

GPIO_PORTF_LOCK_R

Regiszter programozás

Maszkolás writing friendly code
* OR művelettel egy bitet BE kapcsolhatunk; ahova 1-et írunk 1 lesz; ahova 0-t ott nem változik
* AND művelettel egy bitet LE kapcsolhatunk; ahova 0-t írunk 0 lesz; ahova 1-t ott nem változik
* Egyszerűbb annak a bitnek amit le akarunk kapcsolni, az ellentettjét (~) maszkolni AND művelettel. (&)
* Ha le akarok olvasni egy bitet egy regiszterből, & -em a bit helyét.
Gyakori maszkolási értékek

If we wish to access bit

Constant

7

0x0200

6

0x0100

5

0x0080

4

0x0040

3

0x0020

2

0x0010

1

0x0008

0

0x0004


Port címzések

Port Base address
PortA 0x40004000
PortB 0x40005000
PortC 0x40006000
PortD 0x40007000
PortE 0x400240000
PortF 0x40025000


C7 Tervezési és fejlesztési folyamat

Termék életciklusai

  • Probléma meghatározása
  • Tervezés
  • Fejlesztés
  • Tesztelés
  • Üzembe helyezés


Tervezési kritériumok

  • Safety: The risk to humans or the environment
  • Accuracy: The difference between the expected truth and the actual parameter
  • Precision: The number of distinguishable measurements
  • Resolution: The smallest change that can be reliably detected
  • Response time: The time between a triggering event and the resulting action
  • Bandwidth: The amount of information processed per time
  • Maintainability: The flexibility with which the device can be modified
  • Testability: The ease with which proper operation of the device can be verified
  • Compatibility: The conformance of the device to existing standards
  • Mean time between failure: The reliability of the device, the life of a product
  • Size and weight: The physical space required by the system
  • Power: The amount of energy it takes to operate the system
  • Nonrecurring engineering cost (NRE cost): The one-time cost to design and test
  • Unit cost: The cost required to manufacture one additional product
  • Time-to-prototype: The time required to design, build, and test an example system
  • Time-to-market: The time required to deliver the product to the customer
  • Human factors: The degree to which our customers like/appreciate the product

Tippek

"Common Error: Programmers who sacrifice clarity in favor of execution speed often develop software that runs fast, but is error-prone and difficult to change."

"Observation: The easiest way to debug is to write software without any bugs."

"Maintenance Tip: Go from working system to working system."

"Maintenance Tip: It is better to have some parts of the system that run with 100% reliability than to have the entire system with bugs."

"Maintenance Tip: It is better to have a system that runs slowly than to have one that doesn’t run at all."

"Observation:There are two ways of constructing a software design: one way is to make it so simple that there are obviously no deficiencies and the other way is make it so complicated that there are no obvious deficiencies. C.A.R. Hoare, "The Emperor's Old Clothes," CACM Feb. 1981."

Azaz kétféle képen tervezhetünk egy szoftvert:
"Az egyik út hogy annyira egyszerű hogy nyilvánvalóan nincs benne hiba
A másik lehetőség az, hogy olyan bonyolult hogy nincsenek egyértelmű hibák."


Funkciók, eljárások, módszerek, szubrutinok

Ezek kialakítására a a hiba megelőzést segíti.


  • "Make the software project easier to understand"
  • "Increase the number of modules"
  • "Decrease the interdependency (minimize bandwidth between modules)."
Fontos hogy ne keverjük a különböző változókat!

C8 Switches and leds

Leds

Előtét ellenállás számítás:

  • Positive logic: R = VOH-Vd / Id
  • Negative logic: R = 3.3-Vd-VOL / Id
Positive logic: Negative logic:
UT 6 01 LedLimRes PosLogic c8-image007.gif
UT 6 01 LedLimRes NegLogic c8-image007.gif

UTx.6.01 course


C9 Arrays & functional debugging

Debugging Theory

* Black-box testing: "is simply observing the inputs and outputs without looking inside."
* White-box testing: "allows you to control and observe the internal workings of a system."

Common Error: "The most common debugging mistake new programmers make is to simply observe the overall inputs and outputs system without looking inside the device. Then they go to their professor and say, “My program gives incorrect output. Do you know why?”

SysTick timer

Address

31-24

23-17

16

15-3

2

1

0

Name

$E000E010

0

0

COUNT

0

CLK_SRC

INTEN

ENABLE

NVIC_ST_CTRL_R

$E000E014

0

24-bit RELOAD value

NVIC_ST_RELOAD_R

$E000E018

0

24-bit CURRENT value of SysTick counter

NVIC_ST_CURRENT_R

Inicializálás

#define NVIC_ST_CTRL_R      (*((volatile unsigned long *)0xE000E010))
#define NVIC_ST_RELOAD_R    (*((volatile unsigned long *)0xE000E014))
#define NVIC_ST_CURRENT_R   (*((volatile unsigned long *)0xE000E018))
void SysTick_Init(void){
  NVIC_ST_CTRL_R = 0;              // 1) disable SysTick during setup
  NVIC_ST_RELOAD_R = 0x00FFFFFF;   // 2) maximum reload value
  NVIC_ST_CURRENT_R = 0;           // 3) any write to current clears it
  NVIC_ST_CTRL_R = 0x00000005;     // 4) enable SysTick with core clock
}

Example

unsigned long Now;      // 24-bit time at this call (12.5ns)
unsigned long Last;     // 24-bit time at previous call (12.5ns)
unsigned long Elapsed;  // 24-bit time between calls (12.5ns)
void Action(void){      // function under test
 Now = NVIC_ST_CURRENT_R;         // what time is it now?
 Elapsed = (Last-Now)&0x00FFFFFF; // 24-bit difference
 Last = Now;                      // set up for next...
}