Файл: Microcontroller Programming. Thi Micro Chip PIC (Julio Sanchez, 2007).pdf

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Data EEPROM Programming

503

btfsc

STATUS,C

; Did subtract overflow?

goto

bump10

; No. Count subtraction

goto

end10

bump10:

incf

thisDig,f

;increment digit counter

goto

sub10

; Store 10th digit

end10:

movlw

.10

addwf

inNum,f

; Adjust for last subtract

movf

thisDig,w

; get digit counter contents

addlw

0x30

; Conver to ASCII

movwf

asc10

; Store it

; Calculate and store units digit

movf

inNum,w

;

Store units value

addlw

0x30

; Convert to ASCII

movwf

asc1

; Store digit

return

;============================================================ ; EEPROM procedures ;============================================================ ;==============================

;read EEPROM ;==============================

;Procedure to read EEPROM memory. Address of memory

;location to read is stored in local register EEMemAdd

;On exit: read data in w

EERead:

bcf

STATUS,RP0

; Bank

0

movf

EEMemAdd,w

; Address to w

movwf

EEADR

; w to

address register

bsf

STATUS,RP0

; Bank

1

bsf

EECON1,RD

; EE Read

bcf

STATUS,RP0

; Bank

0

movf

EEDATA,w

; W = EEDATA

return

;==============================

;write EEPROM ;==============================

;Procedure to write asc1 byte to EEPROM memory

;Address to write stored in local register EEMemAdd

;Data byte to write is in local register EEByte EEWrite:

;Load byte to write into EE data register

movf

EEByte,w ; Data to w

movwf

EEDATA

; Write

504

Chapter 15

; Set write address in EE address register

movf

EEMemAdd,w

; Address to w

movwf

EEADR

; w to address register

; Write data to EEPROM memory

bsf

STATUS,RP0

; Bank 1

bcf

INTCON,GIE

; Disable INTs.

bsf

EECON1,WREN ; Enable Write

movlw

0x55

; Code # 1

movwf

EECON2

; Write 0x55

movlw

0xaa

; Code # 2

movwf

EECON2

; Write 0xaa

bsf

EECON1,WR

; Set WR bit

; Write operation now takes place automatically

bsf

INTCON,GIE

; Re-enable interrupts

bcf

STATUS,RP0

; Bank 0

return

End

15.2.2 Ser2EEP Program

;File name: Ser2EEP.asm

;Last revision: May 26, 2006

;Author: Julio Sanchez

;PIC: 16F877

;Description:

;Receive character data through RS-232 line and store in

;EEPROM data memory. Received characters are echoed on

;the second LCD line. When <Enter> key is detected (code

;0x0d) the text stored in EEPROM memory is retrieved and

;displayed on the LCD. On startup the top LCD line displays

;the prompt: “Receiving:”. At that time a message “Rdy- ” is

;sent through the serial line so as to test the connection.

;Default serial line setting:

;

2400 baud

;

no parity

;

1

stop bit

;

8

character bits

;

;Program to use 4-bit PIC-to-LCD interface.

;Code assumes that LCD is driven by Hitachi HD44780

;controller and PIC 16F977. Display supports two lines

;each one with 20 characters. The length, wiring and base

;address of each display line is stored in #define

;statements. These statements can be edited to accommodate

;a different set-up.

Data EEPROM Programming

505

;

;WARNING:

;Code assumes 10 Mhz clock. Delay routines must be

;edited for a different clock. Clock speed also determines

;values for baud rate setting (see spbrgVal constant).

;

;===========================

;16F877 switches ;===========================

;Switches used in __config directive:

;

_CP_ON

Code protection ON/OFF

; *

_CP_OFF

;

*

_PWRTE_ON

Power-up timer ON/OFF

;_PWRTE_OFF

;

_BODEN_ON

Brown-out reset enable ON/OFF

; *

_BODEN_OFF

;

*

_PWRTE_ON

Power-up timer enable ON/OFF

;_PWRTE_OFF

;

_WDT_ON

Watchdog timer

ON/OFF

; * _WDT_OFF

;

_LPV_ON

Low voltage IC

programming enable ON/OFF

; * _LPV_OFF

;

_CPD_ON

Data EE memory

code protection ON/OFF

;* _CPD_OFF

;OSCILLATOR CONFIGURATIONS:

;

_LP_OSC

Low power crystal

oscillator

;

_XT_OSC

External parallel

resonator/crystal oscillator

;* _HS_OSC

;_RC_OSC

;|

High speed crystal resonator Resistor/capacitor oscillator (simplest, 20% error)

;|

;|_____ * indicates setup values presently selected

processor 16f877 ; Define processor

#include <p16f877.inc>

__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _HS_OSC & _WDT_OFF & _LVP_OFF & _CPD_OFF

;__CONFIG directive is used to embed configuration data

;within the source file. The labels following the directive

;are located in the corresponding .inc file.

errorlevel -302

; Suppress bank-related warning

;============================================================

;

M A C R O S

;============================================================

; Macros to select the register banks

506

Chapter 15

Bank0

MACRO

; Select RAM bank 0

bcf

STATUS,RP0

bcf

STATUS,RP1

ENDM

Bank1

MACRO

; Select RAM bank 1

bsf

STATUS,RP0

bcf

STATUS,RP1

ENDM

Bank2

MACRO

; Select RAM bank 2

bcf

STATUS,RP0

bsf

STATUS,RP1

ENDM

Bank3

MACRO

; Select RAM bank 3

bsf

STATUS,RP0

bsf

STATUS,RP1

ENDM

;=====================================================

;

constant definitions

; for PIC-to-LCD pin wiring and LCD line addresses ;=====================================================

#define E_line 1

;|

#define RS_line 0

;| — from wiring diagram

#define RW_line 2

;|

; LCD line addresses (from LCD data sheet)

#define LCD_1

0x80

; First LCD line constant

#define LCD_2

0xc0

; Second LCD line constant

#define LCDlimit .20; Number of characters per line #define spbrgVal .64; For 2400 baud on 10Mhz clock

;Note: The constants that define the LCD display

;line addresses have the high-order bit set

;so as to meet the requirements of controller

;commands.

;

;========================================================== ; General Purpose Variables ;==========================================================

;Local variables

;Reserve 20 bytes for string buffer cblock 0x20

strData endc

;Other data

cblock 0x34

; Start of block

count1

;

Counter

#

1

count2

;

Counter

#

2

Data EEPROM Programming

507

count3

; Counter # 3

J

; counter J

K

; counter K

bufAdd

index

store1

; Local storage

store2

endc

;==============================

;Common RAM area ;==============================

;These GPRs can be accessed from any bank.

;15 bytes are available, from 0x70 to 0x7f

cblock 0x70

; For LCDscroll procedure

LCDcount ; Counter for characters per line

LCDline

; Current display line (0 or 1)

; Communications variables

newData

; not 0 if new data received

ascVal

errorFlags

; EEPROM-related variables

EEMemAdd ; EEPROM address to access

EEByte

; Data byte to write

endc

;============================================================

; P R O G R A M

;============================================================

org

0

; start at address

goto

main

; Space for interrupt handlers

org

0x08

main:

;Wiring:

;LCD data to Port-D, lines 0 to 7

;E line -> Port-E, 1

;RW line -> Port-E, 2

;RS line -> Port-E, 0

;Set PORTE D and E for output

;First, initialize Port-B by clearing latches clrf STATUS

clrf PORTB

;Select bank 1 to TRIS Port-D for output Bank1

;TRIS Port-D for output. Port-D lines 4 to 7 are wired

;to LCD data lines. Port-D lines 0 to 4 are wired to LEDs. movlw B’00000000’

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