ICSP help

[electronicsfreak]

Hello. I hate to make another help post, but I am looking for input for this particular project.

I am looking for any suggestions as to what might allow my programmer to program a PIC12F675 in circuit. After already building the board and simply splicing wire leads in to the necessary pins on from the IC socket I have found that attempting to program the PIC fails. I know that there is one/a few things on my particular circuit that may be preventing this thing from being programmed, and I thought I may as well see if anyone has any insight.

At the moment when I am trying to program, MCLR/Vpp is pulled up using a 56Ω resistor, data is pulled up through a resistance near 360kΩ, clock is tied in with the base of a 2N3904 transistor through a 4700Ω resistor, Vdd is at 5V, and Vss is at 0V.
I know that what is hindering my programmer may be fairly obvious, but I am only a mere hobbyist for the moment.

Any suggestions?

 

[Dr_Doggy]

um. im kinda rookie too, but i had similar problem, so i pulled out all the resistors......

also maybe look at the clock, use the internal one and slow it down....

the other thing i do to test that my pic turns on ok is to add a LED to one of the pins and flash it on for 1sec@begining of all my programs(like my check bit! It also relays me my error codes)

 

[DemonicSandwich]

Does this 56Ω pull the pin up to to 5V or does it connect the pin to to the programming voltage wire?
If it connects the pin to 5V or Ground then the pin may not be getting the programming voltage it needs.

That 360Ω may be preventing the data pin from going low while programming.

 

[blueroomelectronics]

What programmer do you have?

 

[be80be]

You'll have to cut MCLR you need at lest 4.7 k pullup to vdd I always use 10 k

And there no way your programmer can bring the data pin low put jumpers on the pins

 

[dons21]

Could you not do something like this, using signal diodes like 1n4148?

 

[be80be]

I would just use jumpers solder jumpers are good if you don't want to use headers pins

 

[electronicsfreak]

blueroomelectronics--This is the programmer I use MPLAB COMPATIBLE PIC PROGRAMMER FOR 8/18/28/40 PIN DEVICES

When I started this project, I originally had no intention of reprogramming this PIC. However, at the moment I can see the value in this. Unfortunately the place this circuit is to be installed is almost impossible to get to easily, so I thought it might be best to run five leads out to a more manageable location. At the moment, though I am running out of room, there are places I can place extra parts on the board.

Here's what the 5 pins are currently connected to. The LED and phototransistor both have the ability to be disconnected, as they are not connected to the main board.

 

[be80be]

You'll not reprogram that the programmer can't over come the load