Vxl Ch06 Laptrinhc8051 p1

7/22/2019 Vxl Ch06 Laptrinhc8051 p1

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I HC QUC GIA TP.H CH MINHTRNG I HC BCH KHOA

KHOA IN-IN T

B MN K THUT IN T

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CHNG 5

Lp trnh C cho 8051(Phn 1)

Bi Minh Thnh

B mn K thut in t -HBK Tp. HCM


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B mnK Thut in T -HBK 2

Ni dung

1. C bn v ngn ng C2. Cc lnh r nhnh v vng lp3. S dng con tr v mng trong C4. Cc hm v chng trnh con5. Chn assembly code trong C

6. M hnh b nh Keil C51


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Ni dung




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B mnK Thut in T -HBK

Gii thiu

C l ngn ng gn ngn ng assembly nht trong tt ccc ngn ng cp cao Lnh tnh ton trn bit

Con tr (nh a ch gin tip)

Phn ln cc vi iu khin u c C compiler Vic pht trin cc ng dng dng C s nhanh chng v

thun li hn assembly.

C l ngn ng lp trnh cu trc (khng phi l hngi tng)

Mi tc v c th c ng gi trong mt hm

Chng trnh chnh c ng gi trong hm main. 4


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C v Assembly

Advantages High-level, structured programming language Compiler relieves programmer from some of the hardware

details

Easier to write large, complex software Programs more readable

Disadvantages Generally larger machine code.

Less control and ability to interact with hardware.

Unclear number of cycles to do something.

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Cu trc mt chng trnh trong C

Cc cu lnh trong C ktthc bng du ;

C phn bit ch hoa v ch

thng Khi vit chng trnh cn

ch vit ch thch

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Cc loi bin trong C

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Dng bin S bit S byte Min gi trChar 8 1 -128 n 127

Unsigned char 8 1 0 n 255Enum 16 2 -32.768 n 32.767Short 16 2 -32.768 n 32.767

Unsigned short 16 2 0 n 65.535

Int 16 2 -32.768 n 32.767Unsigned int 16 2 0 n 65.535

Long 32 4 -2.147.483.648 n 2.147.483.647Unsigned long 32 4 0 n 4.294.697.295

Dng bin S bit S byte Min gi trBit 1 0 0 n 1Sbit 1 0 0 n 1Sfr 8 1 0 n 255

Sfr16 16 2 0 n 65.535

Ngoi ra keil C cn

h tr cc loi bin truy xut ccthanh ghi c chc

nng c bit:



Cc bin m rng trong Keil C

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8051 extension types

bit 8051 bit addressable memory 20h to 2Fh

sbit A bit inside an SFR (e.g. P1.0)

sfr Entire byte of an SFR sfr16

16-bit SFRs (e.g. DPTR) These are special types for accessing 1-bit, 8-bit, and 16-bit special

function registers

Declaration sbit, sfr, and sfr16

Declare outside of main() program Essentially a friendly EQU for an SFR or SFR bit

bit

Declare anywhere a normal variable can be declared



V d

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Bng hng k t

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Cc ton t c bn ca C Multiplicative operators: a*b, a/b, a%b (remainder after division,

e.g. 10 modulo 4 = 2)

Additive operators: a+b, a-b

Equality operators (boolean return): a==b (is equal?), a!=b (is notequal?)

Relational operators (boolean) a=b

Logical operators a==b && a==c (AND), a==c||a (right shift), & (bit-wise AND),^ (bit-wise XOR), | (bit-wise OR), ~ (bit complement)

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Cc ton t c bn ca C Increment and decrement a++, a--, ++a, --a

Unuary operators -a (negative of a), +I, (i), ! (negative logicalvalues), !(a==b) same as (a!=b)

Sizeof operator sizeof(type) (number of bytes of type is returned)sizeof expression (number of bytes of expression returned)

Conditional operator ?. It has the form:

conditionalExpression ? trueExpression1 : falseExpression2

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Th t u tin

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Ni dung

1. C bn v ngn ng C2. Cc lnh r nhnh v vng lp3. S dng con tr v mng trong C4. Chn assembly code trong C

5. M hnh b nh Keil C516. Cc hm v chng trnh con



Cc lnh r nhnh

Cu trc if

Cu trc If else

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Cc lnh r nhnh

Cu trc switch

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Cc lnh vng lp Lnh While

Lnh do while

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Cc lnh vng lp

Lnh for

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Ni dung

1. C bn v ngn ng C2. Cc lnh r nhnh v vng lp3. S dng con tr v mng trong C4. Chn assembly code trong C

5. M hnh b nh Keil C516. Cc hm v chng trnh con


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Con tr trong Assembly

i vi ngn ng assembly, th con tr trong C gn nhtng ng vi nh a ch gin tip v n tngng vi vic s dng cc thanh ghi R0 v R1 lm contr trong vng b nh trong hoc gi tr 2bytes t

trong DPTR tr n vng RAM ngoi MOV R0,#40 R0 cha gi tr 40

MOV R0,#40

MOVX A,@R0 R0 tr n a ch 40 b nh ngoi

Ta cng c th s dng DPTR ch n 64kB b nh ngoi MOVX A,@DPTR c b nh ngoi

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Pointer trong C

Mi bin trong C c 2 thnh phn: Gi tr c lu trong bin

a ch ca bin trong b nh

Pointer l mt bin dng lu gi a ch ca mt

bin khc, v bin m pointer tr n l mt bin cbn.

C php ca con tr:

unsigned char *pointer0;

Du hoa th pha trc c ngha l ni dung cha trong contr l mt a ch ch khng phi l phn d liu s dngtnh ton. Kiu d liu ca bin m pointer0 tr n lunsigned char

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Pointer trong C

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Mng trong C

Mng l mt bin cu trc trong c nhiu phn t cng kiu,mi phn t l mt bin thnh phn ca mng. Mi bin thnhphn ny l mt bin bnh thng v c c s (subscript) phn bit gia phn t ny v phn t kia.

C php ca mngMng mt chiu:

kiu tn_mng*kch_thc+;

Mng hai chiu:

kiu tn_mng*kch_thc_chiu1+*kch_thc chiu2];

V d:unsigned char a[10];

unsigned char a[]={0x00, 0x40, 0x88, 0xC0};

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Con tr v Mng

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temp_array[0]

temp_array[1]

temp_array[2]temp_array[3]

Note: the name of an array is a pointer to the first element:

*temp_array is the same as temp_array[0]

So the following are the same:

n = *temp_array;

n = temp_array[0];

and these are also the same:

n = *(temp_array+5);

n = temp_array[5];


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Cc v d

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Ni dung




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Hm v chng trnh con

Cc hm thng s c gi tr tr v:

V d:unsigned char tinh_tong(unsigned char a, unsigned char b) {

unsigned char tong;

tong=a+b;

return tong;

}

Cn cc chng trnh con th khng c gi tr tr v, m n chthc hin cc lnh bn trong chng trnh v sau quay v li

chng trnh chnh:

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void delay(int time) {

while(time--) {

; /*Khong lam gi ca*/

}

}


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Vit chng trnh cho led chp tt

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S dng hm

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Function prototype

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Function prototype

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//Khai bo ri nh ngha hm sau.


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Truyn i s bng gi tr v bng tham kho

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Ni dung




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Inline assembly

When it is more efficient, or easier, can insertassembly code in C programs.

#pragma asm//put your assembly code here

#pragma endasm

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Chng trnh switch

v led:


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Ni dung




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C51 Memory Models

Small

All variables stored in internal data memory Be carefulstack is placed here too

Generates the fastest, most efficient code

Default model for Keil uVision Projects

Compact All variables stored in 1 page (256 bytes) of external data memory

Accessed using MOVX @R0

Slower than small model, faster than large model

Large

All variables stored in external data memory (up to 64KByte)

Accessed using MOVX @DPTR

Generates more code than small or compact models


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C51 Memory Models (cont)


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Memory type extensions allow access to all 8051 memory types.

A variable may be assigned to a specific memory space The memory type may be explicitly declared in a variable declaration

variable_type variable_name; e.g. int data x;

Program Memory

CODE memory type Up to 64Kbytes (some or all may be located on 8051 chip)

Data Memory 8051 derivatives have up to 256 bytes of internal data memory Lower 128 bytes can be directly or indirectly addressed

Upper 128 bytes shares the same address space as the SFR registers andcan only be indirectly addressed

Can be expanded to 64KBytes off-chip


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code Program memory (internal or external).

unsigned char code const1 = 0x55;//define a constant

char code string1*+ = hello;//define a string

data Lower 128 bytes of internal data memory

Accessed by direct addressing (fastest variable access)

unsigned intdata x;//16-bit variable x

idata All 256 bytes of internal data memory (8052 micro)

Accessed by indirect addressing (slower)


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bdata Bit addressable area of internal data memory (addresses 20H

to 2FH)

Allows data types that can be accessed at the bit level

unsigned char bdatastatus; sbit flag1 = status^0;

xdata External data memory

Slower access than internal data memory

unsigned char xdata var1;


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8051 Memory Usage

In a single chip 8051 application data memory isscarce 128 or 256 bytes on most 8051 derivatives

Always declare variables as the smallest possibledata type Declare flags to be of type bit

Use chars instead of intswhen a variables magnitudecan be stored as 8 bits

Use code memory to store constants and strings


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I/O PROGRAMMING

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Byte Size I/O

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Byte Size I/O (cont)


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Byte Size I/O (cont)

/O


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Bit-addressable I/O

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Bi dd bl I/O ( )


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Bit-addressable I/O (cont)

Bit dd bl I/O ( t)


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Bit-addressable I/O (cont)


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Accessing SFR Addresses 80 - FFH

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Accessing SFR Addresses 80 FFH (cont)


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Using bit Data Type for Bit-addressable RAM

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LOGIC OPERATIONS

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Bit i O t i C


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Bit-wise Operators in C

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Bit i O t i C ( t)


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Bit-wise Operators in C (cont)

Bit i O t i C ( t)


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Bit i O t i C ( t)


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Bit i O t i C ( t)


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Bit i O t i C ( t)


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DATA CONVERSION

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Packed BCD to ASCII Con ersion


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Packed BCD to ASCII Conversion

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ASCII to Packed BCD Conversion


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ASCII to Packed BCD Conversion

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Binary (hex) to Decimal and ASCII Conversion


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Binary (hex) to Decimal and ASCII Conversion

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ACCESSING CODE ROM

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RAM Data Space Usage by 8051 C Compiler


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RAM Data Space Usage by 8051 C Compiler

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RAM Data Space Usage by 8051 C Compiler (cont)


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RAM Data Space Usage by 8051 C Compiler (cont )

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RAM Data Space Usage by 8051 C Compiler (cont)


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RAM Data Space Usage by 8051 C Compiler (cont )

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Accessing code rom Example 1


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Accessing code rom Example 2 (cont)


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Accessing code rom Example 2 (cont )

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Ti liu tham kho


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Ti liu tham kho

H Trung M, Vi x l, Nh xut bn i hc Quc GiaTp. HCM - 2003

I. Scott MacKenzie , The 8051 Microcontroller, 2ndEdition, Prentice-Hall, 1995

Derek Molloy, EE402 - Lecture note Slide bi ging thy H Trung M

Thomas W.Schultz, C and the 8051 Second Edition.

Dogan Ibrahim, Microcontroller Projects in C for the8051, Newnes 2000.

V nhiu ti liu trn mng.

Documents

Vxl Ch06 Laptrinhc8051 p1