16F628 and LMX2306 PLL loading.. help

[kessral]

OK, I have been trying to get this to work in my spare time over the past couple weeks and I seem to have hit a roadblock.

Using a 16F628 PIC I am trying to load bit strings into an LMX2306 PLL chip using SHIFTOUT commands. The PLL is never loading. I used almost Identical code in a Parallax Basic Stamp Homework Board and it worked no problems.

PLL is confirmed working by plugging it into National's codeloader software and also my Parallax board. All connections have been checked many many times. Here is the code if anyone would like to see if I am missing something simple.

Please help me, I know there are some big brains around here.


CODE:-------------------------------------

TRISB = %11111111 'set all pins 0-7 to input
TRISA = %00111100 'set pins 0,1,6,7 to output and pins 2,3,4,5 to input
CMCON = %00000111 'turn off on-board comparators

Include "modedefs.bas"

Low PORTA.6

Pause 500

SHIFTOUT PORTA.7,PORTA.0,MSBFIRST,[0\13, 131\8] 'send F reg
High PORTA.6 'LE high
PAUSE 10
Low PORTA.6 'LE low


SHIFTOUT PORTA.7,PORTA.0,MSBFIRST,[0\9, 4000\12] 'send R reg
High PORTA.6 'LE high
PAUSE 10
Low PORTA.6 'LE low


SHIFTOUT PORTA.7,PORTA.0,MSBFIRST,[1\1, 2566\13, 2\5, 1\2] 'send N reg
High PORTA.6 'LE high
PAUSE 10
Low PORTA.6 'LE low

-------------------------------------:END CODE

[skimask]

You're using Port A.7, which is also OSC1.
Are you sure you've configured the clock correctly to use this pin as an I/O?
http://www.picbasic.co.uk/forum/show...setting+config

Are you sure you're PIC is even running in the first place? How does that blinky LED work?

[kessral]

The LE high and low is not an LED but a Latch enable on the PLL chip to tell it to load in the data in the shift register when shifting is done.

I probably should set an led somewhere to blink to confirm operation of the micro controller. Will do this next.

I am using an MELabs U2 Programmer. It reads and writes no problems. I have set the oscillator to INTRCIO in the MELabs programmer, which should be the internal oscillator?, and still no dice.

[skimask]

I probably should set an led somewhere to blink to confirm operation of the micro controller. Will do this next.

It's always been my 2nd step after a failure...
Actually that's not true. Everything I've built in the past few years has included a 'heartbeat' LED driven by a timer interrupt. LED blinks, no questions as to whether or not the circuit is operating...correctly or otherwise...

[kessral]

Well I changed the code to this:

TRISB = %11111111 'set all pins 0-7 to input
TRISA = %00111100 'set pins 0,1,6,7 to output and pins 2,3,4,5 to input
CMCON = %00000111 'turn off on-board comparators

Include "modedefs.bas"

Low PORTA.1 'for LED
Low PORTA.6

Pause 500

SHIFTOUT PORTA.7,PORTA.0,MSBFIRST,[0\13, 131\8] 'send F reg
High PORTA.6 'LE high
PAUSE 10
Low PORTA.6 'LE low

high porta.1
pause 500 'blink LED
low porta.1

SHIFTOUT PORTA.7,PORTA.0,MSBFIRST,[0\9, 4000\12] 'send R reg
High PORTA.6 'LE high
PAUSE 10
Low PORTA.6 'LE low

high porta.1
pause 500 'blink LED
low porta.1

SHIFTOUT PORTA.7,PORTA.0,MSBFIRST,[1\1, 2566\13, 2\5, 1\2] 'send N reg
High PORTA.6 'LE high
PAUSE 10
Low PORTA.6 'LE low

high porta.1
pause 500 'blink LED
low porta.1

---------------------------------------------
No blinking going on and no highs on an scope from pin 18. Does this mean it is a bad chip even though it reads and writes fine? Or is there something amiss/wrong in my code?

[skimask]

Well I changed the code to this:

well then, change the code to this:

trisb=$ff:trisa=$3c:cmcon=7
main: porta.1=1:pause 500:porta.1=0:pause 500:goto main
goto main

That's known as ol' blinky... See how it's about as simple as you can get...the lowest common denominator...end of the line...edge of the cliff...low man on the pole...last drop in the bucket...
If something like that doesn't work, then I'd be willing to bet that any communications you are trying to do with that LMX2306, or any other chips anywhere in this world (or others) at this time (or any other in the past or the future or otherwise) isn't going to work either.

Does this mean it is a bad chip even though it reads and writes fine?

I've got this car in the backyard. The doors open and close just fine...but it won't start. Does that mean the whole car is bad?

Or is there something amiss/wrong in my code?

Ya think?
Is your circuit perfect? Are you sure? HOW can you be sure? Does the code you've tried run? No? Then you can't be sure your circuit is perfect... ALL you can do is assume.

In other words..............
Break it back down...then build it up in steps...