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

;line addresses have the high-order bit set

;so as to meet the requirements of controller

;commands.

;

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

;Communications variables ascVal

errorFlags

;Temporary storage used by interrupt handler tempW

tempStatus tempPclath tempFsr endc

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

; P R O G R A M

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

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

; main program

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

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

;Data memory bank selection bits:

; 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’

;By default Port-A lines are analog. To configure them

;as digital code must set bits 1 and 2 of the ADCON1

;register (in bank 1)

; make all Port-A lines digial

movwf ADCON1

;Port-B, lines are wired to keypad switches, as follows:

;7 6 5 4 3 2 1 0

;| | | | |_|_|_|_____ switch rows (output)

;|_|_|_|_____________ switch columns (input)

;rows must be defined as output and columns as input

; Enable Port-B pullups for switches in OPTION register

;|__________________________ RBPU (Pullup enable)

;Back to bank 0 Bank0

;Initialize serial port for 9600 baud, 8 bits, no parity

;1 stop

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

; scan keypad

;============================================================ ; Keypad switch wiring:

;|_________________ port B7 |

;Switches are connected to Port-B lines

;Clear scan code register

clrf scanCode ;============================

;scan keypad and display ;============================ keyScan:

;Port-B, lines are wired to pushbutton switches, as follows:

;7 6 5 4 3 2 1 0

;| | | | |_|_|_|_____ switch rows (output)

;|_|_|_|_____________ switch columns (input)

;Keypad processing:

;switch rows are successively grounded (row = 0)

;Then column values are tested. If a column returns 0

;in a 0 row, that switch is down.

;Initialize row code addend

;Initialize row eliminator mask:

;The row mask is ANDed with the key mask to successively

;mask-off each row, for example:

;The row mask, which is initially 1111 1110, is rotated left

;through the carry in order to mask off the next row

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

;shift row mask ;=========================

;Set the carry flag

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

;end of keypad? ;=========================

;Test for last key row (maximum count is 4) decfsz rowCount,f ; Decrement counter goto keyLoop

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

;============================================================ ; display and send data ;============================================================ ;============================================================

;At this point all keys have been tested.

;Variable newScan = 0 if no new scan code detected, else

;variable scanCode holds scan code

;If scan code is in the range 0 to 9, that is, a decimal

;digit, then ASCII conversion consists of adding 0x30.

;If the scan code represents one of the hex letters