Clock Source for WaferCard from PIC16F819

[TKS]

Hi,

I was wondering what if we connect the 16F819.
CLKOUT pin to the clock source of a wafer card.

The 16F819 will then be programmed to use the internal Clock Source.

I'm searching for an way to give the Goldwafer card an clock source
and have no idea how to generate one.

The problem i have is that if hook it up to the 20Mhz osc it stops the pic connected to it from working.

Sowww

what are the ideas???

Regards,

TKs

 

[Nigel Goodwin]

Use a buffer from the oscillator to the card!.

 

[TKS]

how to build the buffer??

cant i just hookup the osc to the card??

what is needed??

tks

 

[Nigel Goodwin]

Re: how to build the buffer??

cant i just hookup the osc to the card??

what is needed??

tks

As you've already found out, often the extra load will stop the clock (particularly at 20MHz), either use a transistor buffer or a spare CMOS logic gate.

 

[TKS]

Ok,

Sow in fact i just need to run the clock ouput from the chip

to the base from an BC374 (the commen used one) and then i just put an

5volt on thecollector of the transitor and the emitter to the clock signal.

Also i put 2 10K's to the base to ground?? and the clock line to ground??
(emitter side)..

Is this right??

Tks

p.s. i also have an HC7400 but i have no idea... if this needs any extra components..

 

[Nigel Goodwin]

I've never had occasion to do it, but there's an application note somewhere at MicroChip about it!.