點字

00=黑黑黑黑.黑黑黑黑

01=黑黑黑黑.黑黑黑__

02=黑黑黑黑.黑黑__黑

7 6 5 4 3 2 1 0

DJNZ的問題

mov A,#80

mov RR1,A

mov A,#2

MOV RR2,A

MOV A,#1

MOV RR3,A //R1 = 80 R2=2

POP A

KO: CLR P3.2

;mov a,#00H

MOVX @DPTR,A

SETB P3.2

INC DPTR

DJNZ R1,KO

DJNZ R2,KO

;DJNZ R3,KO

RET

但當R1跑了80次後，R2-1 = 1 此時R1要從 255開始跑

解法：

用mod概念

假設要480

480 = 255 * 1 + 225

所以r1 設 225

r2設2

就可以得到所求

SP指標位移

考慮下列程式

ORG 0 ;此時(SP)內容值為07H

MOV SP,#9F ;手動將(SP)改設9FH

MOV A,#7 ;Ａ=07H

PUSH A ;(SP)+1 = 0A0H 0A0H=07H

PUSH A ;(SP)+1 = 0A1H 0A1H=07H

POP A ;取值A=07H (SP)-1 = 0A0H

CALL KOO ;設此句CODE為0BH,下句為0EH，則CALL後(SP)+1=0A1H (0A1H)=0EH

(SP)+1=0A2H (0A2H)=00H

KOO: ;假設

MOV A,1

RET ;DPH=(0A1H) (SP)-1 =0A0H DPL=(0A0H) (SP)-1 = 09FH

CALL執行時，會PUSH目前PC值的2BYTES ADDR進(SP)

RET執行時，先POP DPH再POP DPL

0A1H放DPL，0A2H放DPH ，所以完整的RETERN ADDR #000EH

RET

(PC)HIGH <- (sp)

(sp) <- (SP)-1

(PC) LOW <- (SP)

(SP) <- (SP)-1

若(SP) = 09H

PCHIGH = (09H)

PCLOW = (08H)

sp

sp

The Stack Pointer (SP

The Stack Pointer, like all registers except DPTR and PC, may hold an 8-bit (1-byte) value. The Stack Pointer is used to indicate where the next value to be removed from the stack should be taken from.

POINTER指向下一個要被POP出去的東西

When you push a value onto the stack, the 8051 first increments the value of SP and then stores the value at the resulting memory location.

PUSH時，(SP)的值(ADDR)會+1，然後東西會存到(SP)+1的位置

When you pop a value off the stack, the 8051 returns the value from the memory location indicated by SP, and then decrements the value of SP.

POP時，先取值後，才把(SP) -1

This order of operation is important. When the 8051 is initialized SP will be initialized to 07h.

If you immediately push a value onto the stack, the value will be stored in Internal RAM address 08h.

初始的SP值是07H，所以第一個PUSH會被放在08H( INNER RAM )

This makes sense taking into account考慮到 what was mentioned two paragraphs above:

First the 8051 will increment the value of SP (from 07h to 08h) and then will store the pushed value at that memory address (08h).

SP is modified directly by the 8051 by six instructions: PUSH, POP, ACALL, LCALL, RET, and RETI. It is also used intrinsically whenever an interrupt is triggered (more on interrupts later. Dont worry about them for now!).

SHCHR 未完

input

A : ascii code

------------------------------------

SHCHR: ;SHOW CHAR.

MOV DPTR,#EROW24

;CALCULATE PATTERN POSITION

MOV B,#48 ;48 BYTES FOR ONE CHAR

MOV R6,#24 ;24 rows/Char

MUL AB

;一個ascii 佔48bytes

;dptr = erow24 = 1st ascii (ascii code=0 [0~47])

;a*b = ascii code * 48 = 該字的1st byte address

ADD A,DPL

MOV DPL,A

MOV A,B

ADDC A,DPH

MOV DPH,A

;計算memory 位置

MOV A,ROW ;row似乎是1

RL A

RL A

RL A ;*8 ;*8仍是1

MOV B,#TOTCOL*3 ;80*3 //*3不知作啥用

MUL AB ;BA=ROW*1920=ROW*(80*24)

ADD A,COL ;col=2 a=1 -?> a=3

MOV R0,A ;r0=3

MOV A,B ;row * 1920的高位

ADDC A,#GBASE/256 ;a = 0 + c

MOV R1,A

PUSH P1

MOV P1,#0FFH

ASCII code table

FLOC

input

A= ascii code

DPTR = TABOUT的1st位置

output

DPTR = TABLOUT + TABNO * 2 的內容 =>TABNO指向的table 位置

==

A<-TABNO ; 取TABNO，table number按鍵表種類

C=0

A<-TABNO*2

B<-A

A<-(TABNO*2 + TABOUT)

;取值到A，TABOUT為addr 0的話，

;每2bytes為一組(因為是用DW存位置)

;所以多一個number，要跳2bytes

A<=>B ;A換成TABNO*2

A<-(TABNO*2+1 + TABOUT)

;取後半byte的值(低)

DPL<-A

DPH<-B

16進制乘法表

http://upload.wikimedia.org/wikipedia/commons/8/8d/Hexidecimal_Multiplication_Table.png

EROW24

有128個ASCII

全部由DB + 48 bytes 組成

24*16 = 384 = 48 * 8

MUL

(A) <- (A) * (B) 的 bit 0-7 低A

(B) <- (A) * (B) 的 bit 8-15高B

----

A的值 * B的值

----

16bit中 左 8 bit 是低位，右8bit是高位

所以MUL都要先SWAP?

A,ACC

8bits register

ACC是symbolic address

不要直接用A.7, 要用Acc.7作bit address

byte address在 224(E0H)

ref fig 3-3

manual page 3-3

SH1E1

--

Input:

ROW內需有值(row座標，不是address)

Output:

A=07

B=ROW低位*80 + COL座標

丟進parmset

A=08

B=ROW高位*80 + C(低位的進位)

丟進parmset

****************************

A有 8bit , 一個16進制的英文字 = 4 bit

ROW讀進來的8bits 先INC ROW後

分成高4低4

把高4低4交換 why???

低4 bits*80 存到A

高4 bits * 80 存到B

↑錯的

是交換完後，乘完後的高8存B，低8存A

高位是因為低位乘完後超出的部分才放在高位 ，大部分還是在低位

COL有8bit，但COL最大值只有80

若合計值超過 255 則 C = 1 (因為A /8bits 11111111b=255)

****************************

SH1E1:

MOV A,ROW

INC A

SWAP A

MOV B,#80

MUL AB

ADD A,COL

XCH A,B

ADDC A,#0

PUSH A

MOV A,#07H ;CURSOR ADDR. LOW

; MOV B,#0

CALL PARMSET

MOV A,#08H ;CURSOR ADDR. HI

; MOV B,#0

POP B

CALL PARMSET

POP A

POP B

POP DPH

POP DPL

POP RR6

POP RR5

POP RR4

POP RR0

SCRUP: ;DUMMY SCROLL UP. WON'T SCROLL UP IN THIS APPLICATION

RET

ROW

存ROW的memory address

ROW內存的不是address，而是行數

PARMSET

input:

A = 指令種類 (00~08)

B = 指令內容

output:

no return

--------------------------------

PARMSET:

PUSH P1

SETB P3.2 ;DIEN

MOV P1,#LCDSEL

MOV DPTR,#LCDIR ;INDEX REG.

MOVX @DPTR,A

MOV DPTR,#LCDP ;PARAMETER REG.

MOV A,B

MOVX @DPTR,A

POP A

ORL A,#0F0H

MOV P1,A

RET

------------------------