Parts you need to make and how to make a JTAG cable.

[grynner]

c&p,thanks goes to dcoleman5

parts you need to make and how to make a jtag cable.

Parts you need

1)100 ohm ½ watt resistors. (a minimum of five resistors, because you need to test each resistor to make sure they are 100 ohm or close to it. Most of mine were 99.7 ohm’s. To test the ohm’s you have to take a ohm meter and put one lead on one side of the resistor and the other lead on the other side of the resistor. Then you well get your ohm reading take your five closes to a 100 ohm.)

2) 25 pin male parallel printer port connector

3) 20 port female ribbon header (10 pin x 2 row)

4) computer ribbon cable (you only need a 20 strand or less. Most common is a 40 strand ribbon. So just split that in half. The red is colored strand is usually pin 1.)

How to make a jtag cable

Pin out from the 20 pin female header to the 25 pin male parallel printer port connector

9 pin to pin 2
11 pin to pin 3
13 pin to pin 4
15 pin to pin 13
19 pin to pin 5
20 pin ground to pin 18 thru 25 (connect pin 20 from the 20 pin header to all pin’s 18 thru 25 on the 25 pin male parallel printer port connector)

1) connect your 20 pin female header to your computer ribbon. The red colored strand on your ribbon is usually pin one. Also on your 20 pin header it has an arrow that indicates pin one on the 20 pin header. Make sure the computer ribbon is just long enough to make it out of the pansat 2500a to connect to your printer port on your computer. I think your computer ribbon should not be any longer than 7 to 8 inches.

2) then strip back each individual strand. Cut strand 1 thru 8 and then 10, 12, 14, 16, 17, 18 to make it easy to work with. (1 thru 8 and 10, 12, 14, 16, 17, 18 are not used from your 2500a jtag port) strip off enough of the shielding to be able to rap it around your resistor. (about 1 inch is good enough)

3) take your resistors and cut the ends shorter on each side of the resistor. (or just leave them long. It doesn’t matter. You can cut the ends to make it fit better into the 25 pin connector casing after you solder them to the computer ribbon for a cleaner look. Or leave them the length they are and bend them to fit into the casing. The ends are just that long so you can work with them any why you need.) take your pin 9 on your computer ribbon and solder it to one end of one resistor. Then also do that for pin 11, 13, 15. 19.

4) now strip back the shielding from the wires 2, 3, 4, 5, 13 and 18 thru 25 on your 25 pin male parallel printer port connector. (again about 1 inch is good enough.) solder pin 2 from your 25 pin connector to the other end of your resistor going to pin 9 from your 20 pin header. Then solder pin 3 to pin 11, pin 4 to pin 13, pin 13 to 15 and pin 5 to pin 19.

5) solder your pin 20 from your 20 pin connector (this is your grounding pin from your jtag port on your pansat 2500a) to pin’s 18 thru 25 on your 25 pin connector (this is your grounding pin’s from your printer port on your computer.). No external ground is needed. Nor is more than one ground needed.

6) your 25 pin connector should already have the male ends of the wires placed into the 25 pin connector. If not place them in. As you look at the back of your connector where the wires get placed into, the top right port is port 1. (so from right to left) you well place your jtag pin 9 to the pin out port 2 on your 25 pin connector. Pin 11 to 3. Pin 13 to 4. Pin 19 to 5 and pin 15 to 13 which is the last pin out on the top left of your 25 pin connector as you look at it from the back.
As you look at the back of your connector where the wires get placed into, the bottom right port is port 14.
(So from right to left) then you place your grounding pins in 18-25. ************************************************** *** *this picture shows the front view of the, 25 pin connector* ************************************************** ***