Transcript L04_Instruction

AVR CPU Core &
8 bit AVR Instruction Set
안철수 KAIST 석좌교수 "개발자가 성공하는 길"
개발자가 성공하는 길
http://www.devmento.co.kr/devmain/ucc/ucc/ucc_d
etail.jsp?cate_code=ADAFAA&dataSeq=76&main_id=S
UCC1W001
incoming Lab.
Block Diagram of the AVR Architecture
incoming Lab.
AVR Architecture
Flash program memory (16bit)
16 bit x 216 = 2 byte x 64 k = 128 kbyte
Program code가 저장되는 곳
Data Memory (8 bit)
범용 register : 32 byte
I/O register : 64 byte
Ext I/O register : 160 byte
SRAM : 4096byte
변수가 저장되는 곳
PC : Program Counter
address of the instruction being executed
incoming Lab.
Program / Compile / Execution
Program 작성 -> C code 생성
Compile -> hex code 생성
hex code : download 가 가능한 code
machine code (opcode) : 실행 가능한 code
assembly code : machine code의 의미
Execution
start address of program code => PC
Fetch : PC -> flash program memory => machine code -> IR
PC = PC+1 (또는 PC+2)
(IR : instruction register)
Decode : instruction decode
Register Operand Fetch
ALU Operation Execute
Result Write Back
goto Fetch
incoming Lab.
Instruction Execution
Instruction
an element of an executable program
a single operation of a processor
Parallel Instruction Fetches and Instruction Executions
Single Clock Cycle Execution : Harvard architecture
clkCPU : system clock
Atmega 128 : 16MHz 가능, XTAL1 pin으로 공급
실습 kit : 7.3728 MHz (확인요)
incoming Lab.
Single Cycle ALU Operation (in AVR)
Execution Cycle
Execution Time
 1/clkCPU
 clkCPU = 16 MHz ?
 clkCPU = 7.3728 MHz ?
incoming Lab.
8 bit AVR Instruction Set
AVR Instruction Set : http://www.atmel.com
133 Instructions
Instruction
Operation Code + Operand
Operation Code : ALU가 실행할 내용
Operand : ALU가 실행할 대상
Ex) ADC : Add with Carry

‘ADC R1, R2’ 의 opcode 는 ?
incoming Lab.
Operation Code의 유형
Arithmetic and Logic
범용 레지스터간의 사칙연산과 로직 연산
ADC, AND, SUB, AND, OR, …
Branch
Change program counter : 다른 opcode위치로 이동
JMP, BRBC, …
Data Transfer
Load : SRAM등의 Data를 범용 Register로 이동 (LD, LDI, …)
Store : 범용 Register의 값을 SRAM 등으로 이동 (ST, STD, …)
Bit and Bit-Test
Register의 특정 bit을 set(=‘1’)하거나 clear(=‘0’)으로 변경
SBI, CLI, ….
MCU Control
incoming Lab.
Data Addressing Mode : Operand의 유형
Immediate
actual operand
Direct (absolute)
address of operand
Register Direct, I/O Direct, Data Direct
Indirect
Address that specifies (or points to ) operand
Data Indirect, Data Indirect with Displacement, Data Indirect
with Pre-Decrement, Data Indirect with Post-Increment
incoming Lab.
Example) Immediate Addressing
ANDI – Logical AND with Immediate
ANDI r17, $0F
incoming Lab.
Example) Register Direct Addressing
incoming Lab.
Example) Register Direct Addressing
ADD – Add without Carry
ADD r1, r2
ADD r28, r28
incoming Lab.
Example) I/O Direct Addressing
IN - Load an I/O Location to Register
IN r25, $16
incoming Lab.
Example) Data Direct Addressing
LDS – Load Direct from Data Space
LDS
R25, $0100
2 word/2 cycle
incoming Lab.
Data Indirect
X,Y,Z register 사용
incoming Lab.
Example) Data Indirect
LD
incoming Lab.
Example) Data Indirect
CLR R27
LDI R26,$60
LD R0,X+
LD R1,X
LDI R26,$63
LD R2,X
LD R3,–X
incoming Lab.
Status Register
The Status Register contains information about the result
of the most recently executed
SREG
비트
설명
I
Global Interrupt Enable
T
Bit Copy Storage
H
Half Carry Flag
S
Sign Bit
V
2's Complement Overflow Flag
N
Negative Flag
Z
Zero Flag
C
Carry Flag
incoming Lab.
Status Register
비트 7(I : Global Interrupt Enable) :
전체 인터럽트를 허용하도록 설정하는 비트로 SEI 및 CLI 명령으
로 이 비트를 제어할 수 있다.
비트 6(T : Bit Copy Storage) :
BLD, BST 명령을 사용하여 어느 레지스터의 한 비트 값의 복사 가
능.
비트 5(H : Half Carry Flag) :
산술연산의 가감산에서 비트3에서 올림수가 발생하면 1로 세트
BCD 연산에 사용
비트 4(S : Sign Bit) :
플랙 N과 V의 XOR(eXclusive OR)값으로 정수들의 크기를 판단
에 사용.
incoming Lab.
Status Register
비트 3(V : 2's Complement Overflow Flag) :
2의 보수 연산에서 오버플로우를 표시한다.
비트 2(N : Negative Flag) :
연산 결과값의 최상위 비트가 1로 되어 2의 수 표현을 사용하는 경
우 연산 결과가 음수임을 표시.
비트 1(Z : Zero Flag) :
연산 결과값이 0이 되었음을 표시.
비트 0(C : Carry Flag) :
연산으로 자리올림이나 자리내림이 발생하면 1로 세트 된다.
incoming Lab.
Status Register
모든 연산이 실행된 후에 SREG이 변경됨
예) ADD
incoming Lab.
★ JTAG Emulator
JTAG (Joint Test Action Group)
Testing PCBs by using the JTAG Boundary-scan capability
Programming the non-volatile memories, Fuses and Lock bits
On-chip debugging
program download : JTAG emulator
UART 통신 : ISP programmer
incoming Lab.
Instruction Example :
int main(){
unsigned char *a,*b,*c;
a = (unsigned char *)0x100;
b = (unsigned char *)0x101;
c = (unsigned char *)0x102;
*c = *a + *b;
return 0;
}
incoming Lab.
Machine Code(Opcode) / Assembly Code
Compile/Download 후 Debug메뉴의 ‘Start Debugging’
View 메뉴의 ‘Disassembler’
+0000005F:
91900100
LDS
 Load direct from data space
+00000061:
91800101
LDS
 Load direct from data space
+00000063:
0F89
ADD
 Add without carry
+00000064:
93800102
STS
 Store direct to data space
R25,0x0100
R24,0x0101
R24,R25
0x0102,R24
incoming Lab.
Instruction Example :
int main(){
unsigned int *a,*b,*c;
a = (unsigned int *)0x100;
b = (unsigned int *)0x101;
c = (unsigned int *)0x102;
*c = *a + *b;
return 0;
}
incoming Lab.
Machine Code(Opcode) / Assembly Code
Program address
Opcode
Assembly Code
incoming Lab.
Instruction Example :
int main(){
unsigned int *a,*b,*c;
a = (unsigned int *)0x100;
b = (unsigned int *)0x102;
c = (unsigned int *)0x104;
return 0;
}
incoming Lab.
Machine Code(Opcode) / Assembly Code
Program address
Opcode
Assembly Code
incoming Lab.
HEX File
Compile 결과물의 하나
Project directory 아래 “default” 폴더
Intel Hex Format
:100000000C9446000C945D000C945D000C945D0013
:100010000C945D000C945D000C945D000C945D00EC
:100020000C945D000C945D000C945D000C945D00DC
:100030000C945D000C945D000C945D000C945D00CC
:100040000C945D000C945D000C945D000C945D00BC
:100050000C945D000C945D000C945D000C945D00AC
:100060000C945D000C945D000C945D000C945D009C
:100070000C945D000C945D000C945D000C945D008C
:100080000C945D000C945D000C945D0011241FBE67
…
incoming Lab.
Intel Hex Format
:100000000C9446000C945D000C945D000C945D0013
:
10
0000
00
0C 94 46 00 0C 94 5D 00 0C 94 5D 00 0C 94 5D 00
13
incoming Lab.
Intel Hex Format
8-bit
address code
16-bit
0x0000
0C
0x0001
94
Address
code
0x0002
46
0x0000
940C
0x0003
00
0x0001
0046
0x0004
0C
0x0002
940C
0x0005
94
0x0003
005D
0x0006
5D
0x0004
940C
0x0007
00
0x0005
005D
0x0008
0C
0x0009
94
0x000A
5D
0x000B
00
incoming Lab.