WinPic+Tait+16F84A

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Sh@dow

New Member

• Dec 28, 2007

• #21

I measured everithyng with Vdd turned on and:
Vdd +4.88
MCLR +13.17
DATA +4.88
CLOCK +4.88

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Dec 28, 2007

• #22

And do Data and Clock switch between 0V and 5V as you switch then ON and OFF?, and does the Input pin follow the Data pin?.

 

S

Sh@dow

New Member

• Jan 8, 2008

• #23

I found another schematics,which is a bit different.I Modified my programmer ant it works.
I attached the modifications i made.They are the same for Data,Clock and ACK line.

 

Attachments

• Modification.JPG

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P

Pommie

Well-Known Member

Most Helpful Member

• Jan 8, 2008

• #24

But, the original circuit already had the pullups. Didn't you fit them?

Mike.

 

S

Sh@dow

New Member

• Jan 10, 2008

• #25

Original circuit has pinups between chip 74LS07 and PIC.There are no pullups between LPT ant 74LS07.I installed pullups between LPT and 74LS07.

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Jan 10, 2008

• #26

Sh@dow said:

Original circuit has pinups between chip 74LS07 and PIC.There are no pullups between LPT ant 74LS07.I installed pullups between LPT and 74LS07.

Click to expand...

The pullup resistor is absolutely essential, as the buffers are open-collector, and (as expected) it is shown on the original Bob Blick circuit - I just checked the link in your first post!.

Presumably you must have missed it?.