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 Post subject: Advanced Pin Configuration
PostPosted: Mon Mar 17, 2014 7:41 am 

Joined: Mon Mar 17, 2014 7:03 am
Posts: 1

I am building a Parallel Programmer loosely based upon the Tait design. When I open Programmer Selection, and select the Tait Programmer, I see the Advanced Pin Configuration, yet I can find no information about this feature. I can find no Tait derivative programmer designs that use these extra pins.

Are these extra data lines for use with something like a tri-state buffer such as the 74HC125? .... Where, for example, the Data Enable signal goes to the 74HC125 enable pin so that the Data Out of the 74HC125 is high Z when the enable signal is high ?

If not this, then can I get an explanation or direction as to where to find this information? Is there a programmer/ schematic that uses these extra Pins?

I would also like to know how the PicPGM software determines if a programmer is connected. What is it looking for? .... The only thing I can think is that when PicPgm starts up, it sends a few bits of data, while looking for the data on the ACK line.

I have a logic analyzer, but am not sure what I am looking for.

Thanks in Advance

William (AKA cyberroth)

 Post subject: Re: Advanced Pin Configuration
PostPosted: Tue Mar 18, 2014 6:28 pm 

Joined: Fri Oct 28, 2011 5:18 pm
Posts: 220
Hi cyberroth,

the advanced pin configuration allows the configuration of pins for setting enable input of tri-state buffers for clock and data output. E.g. the Microchip AN589 Programmer uses a 74LS244 and the "advanced" pins are used to enable the control clock a data output.

The programmer detection algorithm is quite simple. It sets the data output and checks if the data input follows the state of the input.
  • set data out = high ==> check data in = high
  • set data out = low ==> check data in = low
If this is fullfilled, PICPgm assumes a programmer is connected.

Hope that answers your questions.


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