can 18F452 run with 40Mhz XTL using 5V vcc???

[drbizzarow]

hii

i have a very simple question.
can 18F452 run with 40Mhz Xtl using 5V vcc??? or only 3V volt version can run with 40Mhz Xtl???

 

[wp100]

hii

i have a very simple question.
can 18F452 run with 40Mhz Xtl using 5V vcc??? or only 3V volt version can run with 40Mhz Xtl???

Hi,

If you see the Datasheet Section 22 figs 22-1 and 22-2 it shows that both the standard and LF 452 will run 40mhz but must have a VDD of 4.2v+ and above.

 

[drbizzarow]

thx for quick reply.....
yah !! i have saw it already but need confirmation. thx again.

 

[hexreader]

can 18F452 run with 40Mhz Xtl using 5V vcc??? or only 3V volt version can run with 40Mhz Xtl???

Neither version will work with 40MHz crystal.

If by "Xtl" you mean 2 pin crystal, then the datasheet shows maximum crystal frequency as 25MHz (HS mode).

You can use something like 4 pin canned crystal oscillator of 40MHz in EC or ECIO mode.

... or you can use a 10MHz 2 pin crystal in HS+PLL mode to give the full 40MHz clock.

A 40MHz 2 pin crystal is of no use with PIC18F452.

 

[drbizzarow]

thx hexreader,

can you share me some detail documentation, how i can use 18f452 or 18f4520 with 40Mhz crystal.
actualy i am working on RGB led display i need speed.
thx in advance.

 

[hexreader]

how i can use 18f452 or 18f4520 with 40Mhz crystal.

You cannot use 40MHz crystal.

Use a 10MHz crystal and select HS+PLL mode in configuration bits. This will give you 40MHz CPU clock internally.

 

[drbizzarow]

i have already start googleing it and i am on it....
thx again any way .