Working with Shift Registers and a PIC help - Page 4 - Electronic Circuits Projects Diagrams Free

atferrari · 16th September 2008, 08:30 AM

Hola Dark,

Do you speak as you write? Nonstop until you said all you have to say in a row?

I would not take the pain reading texts like that. Nor listening to a speech like that either.

Look how professionals post here and compare.

futz · 22nd September 2008, 07:17 AM

So I scraped through my transistor bin and found four 2N4403's. I'm not sure how to calculate base resistor values, so I just put 1.2KΩ ones on there. Seems to work ok so far.

Now I need to write proper multiplexing/display handling software for it and build some kewl patterns for it to display.

Pommie · 22nd September 2008, 07:26 AM

Looks good, are you still using the 509?

Mike.

futz · 22nd September 2008, 07:30 AM

Quote:

Originally Posted by Pommie

Looks good, are you still using the 509?

Yes, but only as a bit of a challenge. When I get sick of the 12F509, out it goes and I'll control it with something that has interrupts and a bit more memory, and that I can program in C.

Darkstar64 · 22nd September 2008, 12:50 PM

Hahaha well I did get my hands on a 16f690 a few days ago but im still working with the 509 untill I can figure all this out properly haha but thanks for all the help anyways I have the parts coming in this week hopefully anyways thanks once again guys

futz · 26th September 2008, 01:23 AM

Some progress. I spent a while being confused with the MM5451 chip. I was sure that other shift registers I had worked with shifted to the left (towards the MSB). The 5451's datasheet isn't crystal clear about it, and my test code accidently worked, tho I was shifting the opposite way from what I expected. So when I wrote real code for it I got really strange behaviour. Finally I rewrote to shift to the right and everything works fine now.

I haven't written the multiplexer yet (tonight maybe) but I do have it flashing LEDs properly.

futz · 2nd October 2008, 07:01 AM

Quote:

Originally Posted by skyhawk

Total memory space 1024 words, 512 word pages, so need to set page select bit (PA0) in STATUS register to access all of memory.

I had my 12F509 4x4x4 cube code working nicely - multiplexer/display handler/pattern sequencer all working fine. Then I added another pattern (pushing some of my subroutines beyond the half page limit) and found out what you guys were talking about! Oh boy! What a mess!

I'm just now tinkering with setting/clearing PA0 bits all thru the code to see if I can get it to all work. Sure makes what should be a simple thing into a royal pain in the butt!

I think I hate the 12F509.

What were they thinking? A timer with no interrupt! Paged program memory. Bleh. Soon I'll get disgusted enough to switch to the 12F683.

skyhawk · 2nd October 2008, 12:48 PM

Quote:

I had my 12F509 4x4x4 cube code working nicely - multiplexer/display handler/pattern sequencer all working fine. Then I added another pattern (pushing some of my subroutines beyond the half page limit) and found out what you guys were talking about! Oh boy! What a mess! I'm just now tinkering with setting/clearing PA0 bits all thru the code to see if I can get it to all work. Sure makes what should be a simple thing into a royal pain in the butt!

In addition, subroutine entry points (including tables of retlw) must be in the first 256 words of each page.

Quote:

I think I hate the 12F509. What were they thinking? A timer with no interrupt! Paged program memory. Bleh. Soon I'll get disgusted enough to switch to the 12F683.

Nothing wrong with a 12F509 if you don't try to push it beyond its capabilities. It's not really a hobbyist chip. In a commercial product produced in the 100,000's where every penny counts, it is a cost effective choice if it can do the job. For the hobbyist needing an 8-pin PIC the 12F629, 12F675, or 12F683 is a better choice.

Pins are cheap. To my mind using (a) shift register(s) with an 8-pin PIC makes no sense. It probably takes up more space and costs more than a 18, 28, or 40 pin PIC solution. If you need 28 or 40 pins, the 16F88x family is cheap and very capable.

atferrari · 2nd October 2008, 02:04 PM

Why not to move straight to the 18F family? Easier to program and more powerful.

skyhawk · 2nd October 2008, 02:21 PM

Quote:

Why not to move straight to the 18F family? Easier to program and more powerful.

Well, personally I've never seen the need for an 18F to blink a few LEDs. Now if you were doing a Kalman filter, and a digital control law, and some trig to implement a navigation algorithm I can see the benefit of the bigger program and data space as well as the hardware multiply, but to blink LEDs!

Anyway, to each his own! That's what makes the world interesting.

Darkstar64 · 3rd October 2008, 06:03 AM

futz do you mind posting the assembler for what you have maby I can adapt it for my needs ? also I still can't get ISCP working it might be the hookup im going to test it once again with a ohm meter to make sure its a good connection

futz · 3rd October 2008, 06:41 AM

Quote:

Originally Posted by atferrari

Why not to move straight to the 18F family? Easier to program and more powerful.

You've obviously not read the entire thread.

Here's a quote from higher up this page even:

Quote:

Originally Posted by Pommie

Looks good, are you still using the 509?

Yes, but only as a bit of a challenge. When I get sick of the 12F509, out it goes and I'll control it with something that has interrupts and a bit more memory, and that I can program in C.

I originally picked the 12F509 only because the original poster, Darkstar64, was using it to do a 3x3x3 cube. I first said that it would be difficult (it wasn't, tho the 509's lack of interrupts didn't help any in that regard) and then decided to do a 4x4x4 with it anyway. I'd been wanting to do one for a while anyway. It's much better than the 3x3x3 I did previously.

When I get tired of messing with the 12F509, it'll go in the chip box and I'll connect the cube to something decent that'll make it easy to get it to do what I want. I have lots of PICs - very few of them are little 8-pinners.

futz · 3rd October 2008, 06:51 AM

Quote:

Originally Posted by Darkstar64

futz do you mind posting the assembler for what you have. Maybe I can adapt it for my needs?

See below. It's not terribly impressive, but it works.

Quote:

Also I still can't get ISCP working. It might be the hookup. I'm going to test it once again with a ohmmeter to make sure its a good connection

And you're testing with nothing else except the VPP, PGD and PGC lines connected to the pins? VPP to MCLR (GP3), PGD to GP0, PGC to GP1. The programmer's VDD and Ground must be connected to your target circuit. You need a 10K-33K pullup on the MCLR pin.

Code:

	include	"P12F509.INC"
	__config _IntRC_OSC & _WDT_OFF & _MCLRE_ON

D	equ	0
CP	equ	1

	cblock	0x07
	d1,d2,d3,count,count2,patlen,patrep,temp,anode,offset,fsr1,frames,cathptr
	plex,cath1a,cath1b,cath2a,cath2b,cath3a,cath3b,cath4a,cath4b
	endc

	org	0x000
	goto	init
patt1	addwf	PCL,f
	retlw	0x04			;pattern length - # of frames
	retlw	0x0a			;# of reps

	retlw	0xf0
	retlw	0x00
	retlw	0xf0
	retlw	0x00
	retlw	0xf0
	retlw	0x00
	retlw	0xf0
	retlw	0x00

	retlw	0x11
	retlw	0x11
	retlw	0x11
	retlw	0x11
	retlw	0x11
	retlw	0x11
	retlw	0x11
	retlw	0x11

	retlw	0x00
	retlw	0x0f
	retlw	0x00
	retlw	0x0f
	retlw	0x00
	retlw	0x0f
	retlw	0x00
	retlw	0x0f

	retlw	0x88
	retlw	0x88
	retlw	0x88
	retlw	0x88
	retlw	0x88
	retlw	0x88
	retlw	0x88
	retlw	0x88

patt2	addwf	PCL,f
	retlw	0x04			;pattern length - # of frames
	retlw	0x0a			;# of reps

	retlw	0xf0
	retlw	0x00
	retlw	0xf0
	retlw	0x00
	retlw	0xf0
	retlw	0x00
	retlw	0xf0
	retlw	0x00

	retlw	0x00
	retlw	0x00
	retlw	0x00
	retlw	0x00
	retlw	0x00
	retlw	0x00
	retlw	0xff
	retlw	0xff

	retlw	0x00
	retlw	0x0f
	retlw	0x00
	retlw	0x0f
	retlw	0x00
	retlw	0x0f
	retlw	0x00
	retlw	0x0f

	retlw	0xff
	retlw	0xff
	retlw	0x00
	retlw	0x00
	retlw	0x00
	retlw	0x00
	retlw	0x00
	retlw	0x00

init	movlw	b'11001000'	;clear T0CS for output on GPIO2
	option
	movlw	b'00001000'	;set pins to all outs
	tris	GPIO
	clrf	GPIO		;zero all pins
	movlw	0x08		;set start level
	movwf	anode
	movlw	cathptr		;set cathode pointer
	movwf	cathptr
	clrf	plex		
	bcf	GPIO,D		;init MM5451
	nop
	bsf	GPIO,CP
	nop
	bcf	GPIO,CP

main	call	horiz
	call	vert
	goto	main

horiz	clrf	offset		;point to start of table
	movf	offset,w	;get pattern length
	call	patt1
	movwf	patlen
	incf	offset,f	;get # of reps
	movf	offset,w
	call	patt1
	movwf	patrep
	incf	offset,f
horiz1	call	isr		;multiplex 256 times
	decfsz	plex,f
	goto	horiz1
anim	movlw	0x08		;set bytes per frame counter - 8 bytes
	movwf	count
	movlw	cath1a		;cathode pointer storage
	movwf	FSR
mloop	movf	offset,w	;get a byte of new pattern
	call	patt1
	movwf	INDF
	incf	offset,f	;increment pointers
	incf	FSR,f
	decfsz	count,f		;frame done?
	goto	mloop
	decfsz	patlen,f	;pattern done?
	goto	horiz1
reset	movlw	0x02		;point to start of frames in table
	movwf	offset
	decfsz	patrep,f	;# of reps complete?
	goto	horiz2		;no, fix patlen and go again
	goto	bail		;yes, done
horiz2	movlw	0		;get patlen again
	call	patt1
	movwf	patlen
	goto	horiz1
bail	retlw	0

vert	clrf	offset		;point to start of table
	movf	offset,w	;get pattern length
	call	patt2
	movwf	patlen
	incf	offset,f	;get # of reps
	movf	offset,w
	call	patt2
	movwf	patrep
	incf	offset,f
vert1	call	isr		;multiplex 256 times
	decfsz	plex,f
	goto	vert1
vtanim	movlw	0x08		;set bytes per frame counter - 8 bytes
	movwf	count
	movlw	cath1a		;cathode pointer storage
	movwf	FSR
vtloop	movf	offset,w	;get a byte of new pattern
	call	patt2
	movwf	INDF
	incf	offset,f	;increment pointers
	incf	FSR,f
	decfsz	count,f		;frame done?
	goto	vtloop
	decfsz	patlen,f	;pattern done?
	goto	vert1
vtrst	movlw	0x02		;point to start of frames in table
	movwf	offset
	decfsz	patrep,f	;# of reps complete?
	goto	vert2		;no, fix patlen and go again
	goto	vtbail		;yes, done
vert2	movlw	0		;get patlen again
	call	patt2
	movwf	patlen
	goto	vert1
vtbail	retlw	0

;***************************
;"interrupt" service routine
isr	rlf	anode,f		;change to next level
	movlw	2		;increment cathode pointer
	addwf	cathptr,f
	movlw	0x10		;is anode > 0x08?
	subwf	anode,w
	btfss	STATUS,Z
	goto	shift		;no, go ahead

	movlw	1		;yes, reset to anode 1
	movwf	anode
	movlw	cath1b		;and reset cathode pointer
	movwf	cathptr
shift	movf	cathptr,w	;load FSR
	movwf	FSR
	bsf	GPIO,D		;shift out start bit
	nop
	bsf	GPIO,CP
	nop
	bcf	GPIO,CP

	movlw	0x02		;set byte counter
	movwf	count2
shift5	movlw	0x08		;set loop counter
	movwf	count
	movf	INDF,w		;get a byte
	movwf	temp
shift1	rrf	temp,f		;rotate ms-bit into carry
	btfsc	STATUS,C	;is it 0?
	goto	shift2		;no, shift out a 1
	goto	shift3		;yes, shift out a 0
shift2	bsf	GPIO,D
	nop
	bsf	GPIO,CP		;blip clock
	nop
	bcf	GPIO,CP
	goto	shift4
shift3	bcf	GPIO,D
	nop
	bsf	GPIO,CP		;blip clock
	nop
	bcf	GPIO,CP
shift4	decfsz	count,f		;done 8-bits?
	goto	shift1		;no, go again
	decfsz	count2,f
	goto	shift6
	goto	shanode		;done cathodes - go do anode
shift6	decf	FSR,f
	goto	shift5

shanode	movlw	0x08		;shift out anode byte
	movwf	count
	movf	anode,w
	movwf	temp
shan1	rrf	temp,f
	btfsc	STATUS,C
	goto	shan2
	goto	shan3
shan2	bsf	GPIO,D
	nop
	bsf	GPIO,CP
	nop
	bcf	GPIO,CP
	goto	shan4
shan3	bcf	GPIO,D
	nop
	bsf	GPIO,CP
	nop
	bcf	GPIO,CP
shan4	decfsz	count,f
	goto	shan1

last3	movlw	0x0b		;shift out last 11 bits
	movwf	count
l3loop	bcf	GPIO,D
	nop
	bsf	GPIO,CP
	nop
	bcf	GPIO,CP
	decfsz	count,f
	goto	l3loop
	retlw	0

	end

Darkstar64 · 3rd October 2008, 12:43 PM

I don't have the Pullup resister but yes its islolated using a DIP switch everytime I try to load code it tells me it can't read the OSSCAL or OSSCAL misread or something along those lines thanks for posted the assembler

Darkstar64 · 3rd October 2008, 08:36 PM

Srry Futz im a little confused on the engine part of it and how I would make it work for me with the 8 bit shift regiester's I need to output 2 8 bit strings can you explain it a little more thanks alot I almost have it this is the main engine right ? it takes the 8 bit's in the var temp and shifts them out one at a time clocking inbetween right ? this also loops 8 times so basically all I need to do is write 2 bit strings like this and it should work by the way im using GPIO 1 as the clock now is this correct or am I doing something wrong ? I can't seem to figure this out at all. All come up with a schmatic tonight and post it that im sure will help more then what im trying to just type

Code:

  list      p=12F509            ; list directive to define processor
    #include <p12F509.inc>        ; processor specific variable definitions

    __CONFIG   _MCLRE_ON & _CP_OFF & _WDT_OFF & _IntRC_OSC

; '__CONFIG' directive is used to embed configuration word within .asm file.
; The lables following the directive are located in the respective .inc file. 
; See respective data sheet for additional information on configuration word.



	cblock	0x07
;***** VARIABLE DEFINITIONS
count,temp
D
CP
delay
	endc



;**********************************************************************
RESET_VECTOR    CODE   0x3FF      ; processor reset vector

; Internal RC calibration value is placed at location 0x3FF by Microchip
; as a movlw k, where the k is a literal value.
    
MAIN    CODE    0x000
    movwf   OSCCAL            ; update register with factory cal value 

	movlw	b'00001000'	;set pins to all outs
	tris	GPIO
	
start

	movlw	b'01010101'
	movwf	temp
	movlw	b'11100101'
	movwf	temp
	goto	start
;********Subroutines********

shift5	movlw	0x08		;set loop counter
		movwf	count
		movf	INDF,w		;get a byte
		movwf	temp
shift1	        rrf	temp,f		;rotate ms-bit into carry
		btfsc	STATUS,C	;is it 0?
		goto	shift2		;no, shift out a 1
		goto	shift3		;yes, shift out a 0
shift2	        bsf	GPIO,1
		nop
		bsf	GPIO,1		;blip clock
		nop
		bcf	GPIO,1
		goto	shift4
shift3	        bcf	GPIO,1
		nop
		bsf	GPIO,1		;blip clock
		nop
		bcf	GPIO,1
shift4	        decfsz	count,f		;done 8-bits?
		goto	shift1		;no, go again
		
		END					; End of program !!

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16th September 2008, 08:30 AM	#46
atferrari	Hola Dark, Do you speak as you write? Nonstop until you said all you have to say in a row? I would not take the pain reading texts like that. Nor listening to a speech like that either. Look how professionals post here and compare. __________________ Agustín Tomás In theory, there is no difference between theory and practice. In practice, however, there is. Last edited by atferrari; 16th September 2008 at 08:57 AM.

22nd September 2008, 07:17 AM	#47
futz	So I scraped through my transistor bin and found four 2N4403's. I'm not sure how to calculate base resistor values, so I just put 1.2KΩ ones on there. Seems to work ok so far. Now I need to write proper multiplexing/display handling software for it and build some kewl patterns for it to display. __________________ ========================= Futz's Microcontrollers & Robotics ========================= Last edited by futz; 22nd September 2008 at 07:19 AM.

22nd September 2008, 07:26 AM	#48
Pommie	Looks good, are you still using the 509? Mike.

22nd September 2008, 12:50 PM	#50
Darkstar64	Hahaha well I did get my hands on a 16f690 a few days ago but im still working with the 509 untill I can figure all this out properly haha but thanks for all the help anyways I have the parts coming in this week hopefully anyways thanks once again guys

26th September 2008, 01:23 AM	#51
futz	Some progress. I spent a while being confused with the MM5451 chip. I was sure that other shift registers I had worked with shifted to the left (towards the MSB). The 5451's datasheet isn't crystal clear about it, and my test code accidently worked, tho I was shifting the opposite way from what I expected. So when I wrote real code for it I got really strange behaviour. Finally I rewrote to shift to the right and everything works fine now. I haven't written the multiplexer yet (tonight maybe) but I do have it flashing LEDs properly. __________________ ========================= Futz's Microcontrollers & Robotics ========================= Last edited by futz; 28th September 2008 at 10:46 AM.

2nd October 2008, 02:04 PM	#54
atferrari	Why not to move straight to the 18F family? Easier to program and more powerful. __________________ Agustín Tomás In theory, there is no difference between theory and practice. In practice, however, there is.

3rd October 2008, 06:03 AM	#56
Darkstar64	futz do you mind posting the assembler for what you have maby I can adapt it for my needs ? also I still can't get ISCP working it might be the hookup im going to test it once again with a ohm meter to make sure its a good connection Last edited by Darkstar64; 3rd October 2008 at 06:04 AM.

3rd October 2008, 12:43 PM	#59
Darkstar64	I don't have the Pullup resister but yes its islolated using a DIP switch everytime I try to load code it tells me it can't read the OSSCAL or OSSCAL misread or something along those lines thanks for posted the assembler