Hi Glenn:
The PIC uC chips all divide the incoming oscillator signal by 4 to
generate a set of 4 internal clock signals so the actual instruction
frequency is Fin/4.
A 10 MHz input results in a 2.5 Mhz instruction cycle frequency, or 400
ns per instruction. Any code in the PIC that involves a
Hi Bill,
No, of course it isn't. But for a function as critical
as this, surely one would look at the assembly generated.
There will no doubt be need to adjust things a little bit.
It might end up being something more like:
while(1){
delay_us(4);
#asm
NOP
#endasm
output_t
Does anyone have a good solution for the 1-2 us delay between the
divider "reset" (or "start") and the first (and later) pulses?
I think this might be a good reason to put a serial port on one of the
pins. Then, you could send the divider "skip x steps" or "add x steps."
I'm not sure if it wou
On Sun, 6 Aug 2006 19:40:44 -0700, "Tom Van Baak" <[EMAIL PROTECTED]>
wrote:
>> I don't think any of those chips has a serial port. You would have to do
>> (heroic) bit-banging if you needed that.
>
>True, although simple, robust, and free code samples
>for this are all over the web. Or as Chuck
> If I wanted to divide a 10MHz clock down to 100KHz, I could do something
> like:
> #include <12F629.h>
> #use delay(clock=1000)
> main()
> {
> while(1){
> delay_us(5);
> output_toggle(PIN_A0);
> }
>}
I don't think that will do what I want. The probl
Wait a second - are you saying that the compiler is
smart enough to account for the 'while' and the
'output_toggle' instructions to make the total
execution time for the loop be precisely 50 clock
ticks?
-Original Message-
From: Chuck Harris
If I wanted to divide a 10MHz clock down to 10
Hi Tom,
The CCS C compiler does just fine. When you use the delay function,
it is smart enough to know when it is better to insert a few NOP
instructions (and other time wasters), and when it is better to toss
in a loop. The code it generates is generally better than I can do
myself using assemb
> I don't think any of those chips has a serial port. You would have to do
> (heroic) bit-banging if you needed that.
True, although simple, robust, and free code samples
for this are all over the web. Or as Chuck mentioned,
serial support is included in various PIC compilers.
One caution, thou
Hal Murray wrote:
>> Right, this is essentially what my (and any other) PIC divider does.
>> Simple, isn't it?
>
>> And those 8-pin PICs are too cute to pass up.
>
> Yup. I saw the light when I was trying to work out a 1/2 second delay with
> something like a 555. I couldn't quite get what I w
> Right, this is essentially what my (and any other) PIC divider does.
> Simple, isn't it?
> And those 8-pin PICs are too cute to pass up.
Yup. I saw the light when I was trying to work out a 1/2 second delay with
something like a 555. I couldn't quite get what I wanted. Simple in
software.
>While we are on the subject of PIC dividers, and if the lower
> order outputs (other than 10kHz) are not required, the standard
> divide-by-1000 part of a GPS-derived standard may easily be
> implemented in an 8-pin 12F629/675 saving one chip and 20 pins.
>
>
> My code, such as it is -
Joe,
Hi Joe:
The PIC 10F200 in a SOT-23 would really be minimal.
Have Fun,
Brooke Clarke
--
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com
Joe McElvenney wrote:
>Hi,
>
> While we are on the subject of PIC dividers, and if
Hi,
While we are on the subject of PIC dividers, and if the lower
order outputs (other than 10kHz) are not required, the standard
divide-by-1000 part of a GPS-derived standard may easily be
implemented in an 8-pin 12F629/675 saving one chip and 20 pins.
My code, such as it is -
Setup the
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