_xinfreq = 5_000_000 and 6_250_000 clock speed

Jkane

Hello

I have a question on the xinfreq parm,

_clkmode = xtal1 + pll16x
_xinfreq = 5_000_000 'Set to standard clock mode and frequency (80 MHz)

I purchased the 6.250 crystal, so the statement looks like this

_clkmode = xtal1 + pll16x
_xinfreq = 6_250_000 'Set to standard clock mode and frequency (100 MHz)

and replaced the crystal on the demo board,

then I wrote some assembler to test it, my scope results showed 12.5 ns as the min (toggling a pin)

1/80,000,000 = 0.0000000125

but when I replaced the crystal with 6.25 Mhz I expected 10 ns but I received the 12.5 again

1/100,000,000 = 0.000000010

but in reading it seems that 80Mhz is the limit, regardless, and above 6.25 mhz things get slightly unstable.

my assembler was simply

time = cnt
time + delta
:loop
xor pin ' toggle pin
waitcnt(time,delta) ' the lowest delta I could get was 4, below that there was no toggle
jmp #:loop

anyway, I was just curious, I would like 100Mhz, it I can get it.

regards

Jeff

Bill Henning

your code has many errors... am typing on a tablet, so i cant correct it

the minimum loop would be

mov dira,#1 ' enable P0 for output

loop xor outa,#1
jmp #loop

which would take 8 clock cycles

scope should show 5Mhz square wave with 5mhz xtal, and 6.25mhz with 6.25mhz crystal

Jkane

Hello,

5Mhz would give you 200ns, by using the x16 multipler you get much faster, but what I was getting at is that yes, there are 8 cycles, but the cycles are faster, therefore the switch is faster and the toggle should happen faster. but since I am not getting what it think I got it wrong.

regards

Jeff

Duane Degn

If you post your actual code instead of pseudo code, we might be able to help you better.

Make sure and use code tags when posting code.
[noparse]

' your code here

[/noparse]

will show up as:

' your code here

Jeffrey Kane

Hello,

I moved over to the super carrier board, works correctly

thanks

Jeff

Duane Degn

Jeffrey Kane wrote: »

Hello,

I moved over to the super carrier board, works correctly

thanks

Jeff

I'm confused. How did switching to a board for the Basic Stamp fix your Propeller issue?

Jkane

I was using the propeller activity board, my connections were probably bad, so the clocking seemed to get messed up, when i converted to the propeller project board and did better connections, things seemed to be exactly what i expected.

regards

jeff

Duane Degn

Jkane wrote: »

I was using the propeller activity board, . . . when i converted to the propeller project board

That explains things. Just a mix up on the name.

Thanks.