03/28/1436

University of Kashan Faculty of Electrical and Computer Engineering Department of Computer Engineering

Lecture note 7

AVR Advanced Assembly Language Programming Different Addressing Modes Hossein Sabaghian-Bidgoli [email protected] Fall 2014

Assembler Directives  .INCLUDE,

.ORG, .EQU, .SET, .DEF  Arithmetic Expression (+-*/%)

 Logic

Expression (&|^~)

 Shift

Operators ()

2

1

Microprocessors

University of Kashan

03/28/1436

Assembler Directives  An

Application of Shift Operators ()

3

Microprocessors

University of Kashan

Assembler Directives  HIGH()

4

2

and LOW() Functions

Microprocessors

University of Kashan

03/28/1436

Addressing Modes 

Data   

Immediate Register Memory 

Data memory  



Program memory



EEPROM





Indirect ((Auto inc)

IO  



Direct Register Indirect (Auto inc, Auto Dec, With displacement)

Direct Bit

Program (label)   

Absolute (long) Relative(Short) Indirect

5

Microprocessors

University of Kashan

Addressing Modes  Single Register Addressing  Immediate

6

3

Addressing

Microprocessors

University of Kashan

03/28/1436

Addressing Modes  Two

Register Addressing

7

Microprocessors

University of Kashan

Addressing Modes  Data

Direct Addressing

Examples: STS 0x1000,R16

8

4

Microprocessors

University of Kashan

03/28/1436

Addressing Modes  IO Direct

5

Addressing

9

Microprocessors

University of Kashan

10

Microprocessors

University of Kashan

03/28/1436

 Register Indirect

Examples: LD R16, Y ST Z, R16

11

Microprocessors

University of Kashan

Microprocessors

University of Kashan

 Register Indirect

12

6

03/28/1436

13

Microprocessors

University of Kashan

Addressing Modes  Register Indirect with

Pre-Decrement

Examples: LD R16, -Z ST -Z, R16 14

7

Microprocessors

University of Kashan

03/28/1436

Addressing Modes  Register Indirect with

Post-Increment

Examples: LD R16, Z+ ST Z+, R16 15

Microprocessors

University of Kashan

Addressing Modes  Register Indirect With

Displacement

Examples: LDD R16, Y+0x10 STD Z+0x20, R16 16

8

Microprocessors

University of Kashan

03/28/1436

Addressing Modes  Register Indirect

17

Microprocessors

University of Kashan

Look up Table  .DB   

18

9

Define Bytes in program memory Program memory is word addressable Assembler align to even address

Microprocessors

University of Kashan

03/28/1436

Look up Table  .DW 

Define Words in program memory

19

Microprocessors

University of Kashan

Addressing Modes  Program

Memory Addressing

Examples: LPM Rn, Z

20

10

Microprocessors

University of Kashan

03/28/1436

Addressing Modes  Program

Memory Addressing with Post Increment

Examples: LPM Rn, Z+

21

Microprocessors

University of Kashan

Addressing Modes  Indirect Program

Addressing

Examples: IJMP ICALL

22

11

Microprocessors

University of Kashan

03/28/1436

Addressing Modes  Relative Program

Addressing

Examples: RJMP RCALL 23

Microprocessors

University of Kashan

Look up Table  The value of Z

24

12

Microprocessors

University of Kashan

03/28/1436

Look up Table  The value of

25

Z

Microprocessors

University of Kashan

Read a string from flash and send to output PortB

26

13

Microprocessors

University of Kashan

03/28/1436

Example 6-17 Read a string from flash memory char by char , Write them to SRAM

27

Microprocessors

University of Kashan

Example 6-18 Get a 3-bit number from PortC , Put corresponding Ascii code to PortD

28

14

Microprocessors

University of Kashan

03/28/1436

Example 6-19 Get a 4-bit number x from PortB , catch x2 from a look-up table, put to PortD

29

Microprocessors

University of Kashan

Example 6-20 Get a 4-bit number x from PortB , put x2+2x+3 to PortC (Use a look-up table)

30

15

Microprocessors

University of Kashan

03/28/1436

LED on the Output Ports Vcc=+5V



Correct cases    



Case1: LED is ON if output=zero Case2: LED is ON if output=One Most LEDs drop 1.7 volts and need about 10ma Current is (5-1.7)/470

Case1

OK

Output Pin

Case2

Incorrect cases 

 



Too much current Failure of Port or LED

Output Pin

Output Pin

Case4

Case5: LED is ON if output=1   



Vcc=+5V

Case3

Case3 and case4:

Output Pin

470

Appropriate for open collector output (NPN) Else (if no open collector) failure of Port or LED when 1 High power consumption Case5

Vcc=+5V

Case6: LED is ON if output=0   

Appropriate for open collector output (PNP) Else (if no open collector) failure of Port or LED when 0 High power consumption

31

Microprocessors

470

Output Pin

Vcc=+5V

Case6 Output Pin 470

University of Kashan

The 7-segment Display (Cont.)  7-segment displays come

Common Anode Connect cathodes to the output

16

in 2 configurations:

Common Cathode Connect Anode to the output

03/28/1436

BCD to 7_Seg lookup table a f

b g

e

BCD

pgfedcba 7_seg

he x

0000

001111 11

3f

0001

00110000

30

0010

0101101 1

5b

0011

010011 11

4f

0100

011001 10

66

b

0101

01101101

6d

c

0110

01111101

7d

0111

00000111

07

1000

01111111

7f

1001

01101111

6f

c d

a

a f e

f

d a

b

f

c

e

g

d

g

e

c d

tab_7sg: .db .db

f

b

g

c

d

a

g

b c

d f

c

b

e a

g

a

a b

f

c

e

g

a b

f

g

c d

d

0x3f,0x30,0x5b,0x4f,0x66, 0x6d 0x7d,0x07,0x7f,0x6f

33

Microprocessors

University of Kashan

Example: Read Data from SRAM .include "m16def.inc" .org 0 LDI R17, High(RAMEND) OUT SPH, R17 LDI R17, LOW(RAMEND) OUT SPL, R17

;--->

LDI STS LDI STS LDI STS LDI STS

UP:

34

17

R17, 0x60, R17, 0x61, R17, 0x62, R17, 0x63,

0b00000110 R17 0b01001111 R17 0b11101111 R17 0b01001111 R17 ;--->

LDI OUT

R17, 0xff DDRC, R17

LDI LDI LDI

YL, YH, R16,

LD OUT CALL DEC BRNE jmp

R17, Y+ PORTC,R17 DELAY R16 UP REPEAT

REPEAT:

Microprocessors

0x60 0x00 4

University of Kashan

03/28/1436

Example: Read Data from SRAM .include "m16def.inc" .org 0 LDI R17, High(RAMEND) OUT SPH, R17 LDI R17, LOW(RAMEND) OUT SPL, R17

;--->

LDI STS LDI STS LDI STS LDI STS

UP:

R17, 0x60, R17, 0x61, R17, 0x62, R17, 0x63,

0b00000110 R17 0b01001111 R17 0b11101111 R17 0b01001111 R17 ;--->

35

LDI OUT

R17, 0xff DDRC, R17

LDI LDI LDI

YL, YH, R16,

LD OUT CALL DEC BRNE jmp

R17, Y+ PORTC,R17 DELAY R16 UP REPEAT

REPEAT:

Microprocessors

0x60 0x00 4

University of Kashan

Example: Read Data from Code Memory .include "m16def.inc" .org 0 LDI R17, High(RAMEND) OUT SPH, R17 LDI R17, LOW(RAMEND) OUT SPL, R17 LDI STS LDI STS LDI STS LDI STS

36

18

R17, 0x60, R17, 0x61, R17, 0x62, R17, 0x63,

0b00000110 R17 0b01001111 R17 0b11101111 R17 0b01001111 R17 ;--->

;--->

LDI OUT

R17, 0xff DDRC, R17

LDI LDI LDI

ZL, ZH, R16,

REPEAT: LOW(Data1