Scoreboard display on LCD (edsim51)

Hello! I'm currently learning the basics of microcontrollers and was given the task of creating a scoreboard to display on the LCD (so 4 digits) and have switches to increment and decrement each displayed digit in assembly. So something like:

0000

Switch 1 and 2, decrements and increments the first digit, 3 and 4 for the second... so on and so forth.

Hitting switch 2 from this point would show: 1000

Switch 4 woudl show: 1100

Etc.

I've figure out how to output to the LCD (thanks to the edsim51 examples) so that my program shows "0000" when run, but I'm not sure how to implement the rest of my code.

I'm not asking how to be spoon fed how to do it but more like I could use some guidance. Would it be possible to use the "switch banks" on the screen to do this? There ARE 8 of them. And do I have to use interrupts to increment and decrement the counters?

If it's of any help here's the code I have written to display "0000" on the LCD:

; put data in RAM
	MOV 30H, #'0'
	MOV 31H, #'0'
	MOV 32H, #'0'
	MOV 33H, #'0'
	MOV 34H, #0; end of data marker


; initialise the display
; see instruction set for details


	CLR P1.3		; clear RS - indicates that instructions are being sent to the module

; function set	
	CLR P1.7		; |
	CLR P1.6		; |
	SETB P1.5		; |
	CLR P1.4		; | high nibble set

	SETB P1.2		; |
	CLR P1.2		; | negative edge on E

	CALL delay		; wait for BF to clear	
					; function set sent for first time - tells module to go into 4-bit mode
; Why is function set high nibble sent twice? See 4-bit operation on pages 39 and 42 of HD44780.pdf.

	SETB P1.2		; |
	CLR P1.2		; | negative edge on E
					; same function set high nibble sent a second time

	SETB P1.7		; low nibble set (only P1.7 needed to be changed)

	SETB P1.2		; |
	CLR P1.2		; | negative edge on E
				; function set low nibble sent
	CALL delay		; wait for BF to clear


; entry mode set
; set to increment with no shift
	CLR P1.7		; |
	CLR P1.6		; |
	CLR P1.5		; |
	CLR P1.4		; | high nibble set

	SETB P1.2		; |
	CLR P1.2		; | negative edge on E

	SETB P1.6		; |
	SETB P1.5		; |low nibble set

	SETB P1.2		; |
	CLR P1.2		; | negative edge on E

	CALL delay		; wait for BF to clear


; display on/off control
; the display is turned on, the cursor is turned on and blinking is turned on
	CLR P1.7		; |
	CLR P1.6		; |
	CLR P1.5		; |
	CLR P1.4		; | high nibble set

	SETB P1.2		; |
	CLR P1.2		; | negative edge on E

	SETB P1.7		; |
	SETB P1.6		; |
	SETB P1.5		; |
	SETB P1.4		; | low nibble set

	SETB P1.2		; |
	CLR P1.2		; | negative edge on E

	CALL delay		; wait for BF to clear


; send data
	SETB P1.3		; clear RS - indicates that data is being sent to module
	MOV R1, #30H	; data to be sent to LCD is stored in 8051 RAM, starting at location 30H
loop:
	MOV A, @R1		; move data pointed to by R1 to A
	JZ finish		; if A is 0, then end of data has been reached - jump out of loop
	CALL sendCharacter	; send data in A to LCD module
	INC R1			; point to next piece of data
	JMP loop		; repeat

finish:
	JMP $


sendCharacter:
	MOV C, ACC.7		; |
	MOV P1.7, C			; |
	MOV C, ACC.6		; |
	MOV P1.6, C			; |
	MOV C, ACC.5		; |
	MOV P1.5, C			; |
	MOV C, ACC.4		; |
	MOV P1.4, C			; | high nibble set

	SETB P1.2			; |
	CLR P1.2			; | negative edge on E

	MOV C, ACC.3		; |
	MOV P1.7, C			; |
	MOV C, ACC.2		; |
	MOV P1.6, C			; |
	MOV C, ACC.1		; |
	MOV P1.5, C			; |
	MOV C, ACC.0		; |
	MOV P1.4, C			; | low nibble set

	SETB P1.2			; |
	CLR P1.2			; | negative edge on E

	CALL delay			; wait for BF to clear

delay:
	MOV R0, #50
	DJNZ R0, $
	RET

You should start by putting you display code into subroutines.
One to initialise and a second to display the string at 30h

There is no need to use interrupts yet.
Poll (read repeatedly) the 8 buttons in turn,
it will be easiest to wait until a key is pressed and released.

The method is quite simple.
If an up key is pressed, increment the value unless it is already at '9'.
If a down key is pressed, decrement the value unless it is already at '0'.
Every time a key press is found, refresh the display.

Would it be possible to use the "switch banks" on the screen to do this?
There ARE 8 of them.

Reiniku

Sorry, don't know what they are.

hi Reiniku
can u give more info on ur project
what ur idea
how much u done whats next u want where ur getting problem
need some detail here

The original idea was proposed as:

"The idea is to display the count on the LCD display. Using switches, a user can increment and decrement a counter. After every press of a switch, the subsequent count can be seen on the LCD display. There are 4 counters that have to be seen on the LCD. Use two switches per one counter: first switch as incrementer, second as decrementer."

So far all I have is the digits displayed on the LCD. I'm very very new at assembly so I'm not really sure how to continue.

I have the code written listed above. I'm fortunate since this is all done on edsim51 to simulate 8051.

hi Reiniku
ru bound to do it asm if not then why not in c
that is easy as compare to asm
u can use interrupts to counts
increment and decrements
let say to take a start u need an external interrupts
download this book and read its interrupt chapter
ita a mazidi book
1) http://ifile.it/l3t8e4k/The_8051_Microcontroller_and_Embedded_Systems_Using_Assembly_and_C-2nd-ed_BY_Mazidi.rar

or

2) http://ifile.it/l3t8e4k

I'm bound to asm by the project's guidelines to familiarize myself with hardware interaction. I will go and read the chapter as you have suggested.

hi Reiniku
here is a sample code i comment it properly for ur easy understanding
lcd is in 4- bit mode
external interrupts r used also as a sample
when an interrupt occur a register increment
this increment is displayed on lcd too
Proteus file is included

Hello! Thank you for the sample code. I am reading through it right now to get an understanding and I am attempting to run it in the edsim51 simulation but it does not recognize "db" as part of its instruction set. Is this abnormal? Sorry for the trouble.

It says:

Syntax Error - DB statement - DB " HELLO WORLD ",0H

when attempting to assemble.

hi Reiniku
oho ur using edsim51
but i make it in keil
why ur not using keil

It's part of the supplied tools given by my intrsuctor with its manual. The whole class is to use edsim51 so we are streamlined and can compare code on our different projects as we progress.

The problem is that we were instructed to use this but not HOW to use it, so I've been lost for quite a bit.

It does recognize db when used in this manner

LEDcodes:	; | this label points to the start address of the 7-segment code table which is 
		; | stored in program memory using the DB command below
	DB 11000000B, 11111001B, 10100100B, 10110000B, 10011001B, 10010010B, 10000010B, 11111000B, 10000000B, 10010000B