prog47c.asm

主要是8051源代码

;  PROG47c - Working through the Electronic Breakout Box  
;
;
;  Start Taking User Input.  
;
;  PROG47C - Output a Table and Save the Blank Positions in R5, R6 and R7 
;
;  Myke Predko
;  98.06.20
;
;  Hardware Notes:
;  DS87C520 is used as the Microcontroller
;   - Oscillator Speed is 11.052 MHz
;  P2.4-7 are the LCD Data Bits (NOTE: Bits Are Reversed)
;  P0.3 is Pulled up with a 4.7L K resistor and used for the LCD "RS" Bit
;  P0.4 is Pulled up with a 4.7K Resistor and used for the LCD "E" Bit

;  Constant Declarations
define RS=P0.3                  ;  Define the LCD "RS" Bit
define EStrobe=P0.4             ;  Define the LCD "E" Bit

;  Variable Declarations


;  Macros


;  Mainline
 org 0                          ;  Execution Starts Here
MainLine:                       ;  Mainline of the Program

  acall   LCDInit               ;  Initialize the LCD

  mov     A,#3                  ;  Display The Forth Message
  acall   MsgSend               ;  Output the Message

;  #### - Put in Function Code Here
  
Loop:                           ;  Loop Here forever
  ajmp    Loop


;  Subroutines
MsgSend:                        ;  Send the Specified Message to the Display

  mov     R1,A                  ;  Save the Message Number

  mov     R0,#0                 ;  Use R0 as the Offset Counter

MsgSend_Find:                   ;  Look for the Appropriate Message

  mov     A,R1                  ;  Are we Now At Zero?
  jz      MsgSend_Output        ;   If Count is Zero

  mov     A,#LOW(MsgSendTable-MsgSendFindGet)
  add     A,R0                  ;  Get Current Address

  movc A,@A+PC                  ;  Get the Character in the Displays
MsgSendFindGet:

  inc     R0                    ;  Point to the Next Character

  jnz     MsgSend_Find          ;  If NOT Equal to Zero,
  
  dec     R1                    ;  It is, Decrement the Message Counter

  ajmp    MsgSend_Find

MsgSend_Output:                 ;  Now, Output the String to '\0'

  mov     2,R0                  ;  Save the Start of the Message

  mov     R5,#0FFh              ;  Set the Registers As Invalid
  mov     R6,#0FFh
  mov     R7,#0FFh

  setb    RS                    ;  Make Sure Characters Are going out

MsgSendOutput_Loop:             ;  Output Each Character in the Table to "\0"

  mov     A,R0
  add     A,#LOW(MsgSendTable-MsgSendOutputGet)

  movc A,@A+PC                  ;  Read the Table
MsgSendOutputGet:

  inc     R0                    ;  Point to the Next Character

  jz      MsgSendOutput_Check   ;  If at Zero, Stop the Reading

  mov     R1,A                  ;  Save the Character
  acall   CharSend

  cjne    R1,#' ',MsgSendOutput_Loop

  mov     5,R6                  ;  Save the Blank Position
  mov     6,R7
  mov     A,R0                  ;  Calculate the Offset
  setb    C
  subb    A,R2
  mov     R7,A

  ajmp    MsgSendOutput_Loop

MsgSendOutput_Check:            ;  Now, Shift down the Blanks

  mov     A,R7                  ;  Do we Have No Blanks?
  xrl     A,#0FFh
  jz      MsgSend_End

MsgSendOutputCheck_Loop:        ;  May Only Have One Blank

  cjne    R5,#0FFh,MsgSend_End  ;  Everything Shifted Down

  mov     5,R6                  ;  Shift the Data Down Until All Blanks Saved
  mov     6,R7
  mov     R7,#0FFh

  ajmp    MsgSendOutputCheck_Loop

MsgSend_End:                    ;  Message Output and Blanks Setup

  ret

MsgSendTable:                   ;  Messages to be Displayed
  db      'Left  ', 0           ;  Message  0
  db      'Right ', 0           ;  Message  1
  db      'BREAKOUT BOX',0      ;  Message  2
  db      ' Run Configure',0    ;  Message  3
  db      'Speed',0             ;  Message  4
  db      ' 110 300 Cont',0     ;  Message  5
  db      'Speed -',0           ;  Message  6
  db      ' 1200 2400 Cont', 0  ;  Message  7
  db      'Speed |',0           ;  Message  8
  db      ' 9600 19200 Cont',0  ;  Message  9
  db      'Port Type',0         ;  Message 10
  db      ' DCE DTE',0          ;  Message 11
  db      'Modem Ctrl',0        ;  Message 12
  db      ' Enble Loop None',0  ;  Message 13
  db      'Display',0           ;  Message 14
  db      ' String Byte/Bit',0  ;  Message 15


LCDInit:                        ;  LCD Initialize Blank Offsets

  clr     EStrobe               ;  Make Sure the "E" Line is Low

  acall   Dlay5                 ;  Wait 30 msecs for the LCD to Power Up
  acall   Dlay5
  acall   Dlay5
  acall   Dlay5
  acall   Dlay5
  acall   Dlay5

  clr     RS                    ;  Sending Instructions

  mov     P2,#0C0h              ;  Output the Reset Command
  setb    EStrobe               ;  Try this instead of "E"?
  clr     EStrobe

  acall   Dlay5

  setb    EStrobe               ;  Send the Reset Again
  clr     EStrobe

  acall   Dlay200               ;  Wait 200 msecs

  setb    EStrobe               ;  Send Reset for the Last Time
  clr     EStrobe

  acall   Dlay200

  mov     P2,#040h              ;  Now, Put the LCD in 4 Bit Mode
  setb    EStrobe
  clr     EStrobe

  acall   Dlay200

  mov     A,#028h               ;  Set the Number of Display Lines to 2
  acall   CharSend              ;   and a 5x7 Font

  mov     A,#008h               ;  Turn the Display Off
  acall   CharSend

  mov     A,#001h               ;  Clear the Display RAM
  acall   CharSend

  mov     A,#006h               ;  Enable Cursor Increment
  acall   CharSend

  mov     A,#00Eh               ;  Turn on the Display
  acall   CharSend

  ret


CharSend:                       ;  Send the Character in the Accumulator

  mov     R3,#8                 ;  Have to Reverse the Bits
CSLoop:                         ;  Loop Here Until R4 Has the Value Reversed
  rrc a                         ;  Shift the LSB into the Carry Flag
  xch     A,R4                  
  rlc a                         ;  Shift in the New MSB
  xch     A,R4
  djnz    R3,CSLoop             ;  Loop Around

  xch     A,R4                  ;  Save R4 for Tests

  swap a                        ;  Make Low Byte high Byte...
  mov     P2,A                  ;  Output the High Nybble First
  setb    EStrobe
  clr     EStrobe

  swap A                        ;  Now, Output the Low Nybble
  mov     P2,A
  setb    EStrobe
  clr     EStrobe

  acall   Dlay200

  jb      RS,CharSendEnd        ;  If Outputting a Character, Not a Long Instruction

  anl     A,#03Fh               ;  Are we Executing a Long Instruction?
  jnz     CharSendEnd

  acall   Dlay5                 ;  Yes, Delay 5 msec

CharSendEnd:

  ret


Dlay200:                        ;  Use R7 to Delay 200 usecs

  mov     R3,#192
Dlay200Loop:
  djnz    R3,Dlay200Loop        ;  3 Cycles

  ret


Dlay5:                          ;  Use R6 and R7 to Delay 5 msecs

  mov     R3,#0
  mov     R4,#19
Dlay5Loop:
  djnz    R3,Dlay5Loop          ;  3 Cycles
  djnz    R4,Dlay5Loop          ;  3x256 + 3 = 771 Cycles

  ret