unwink buffered jtag

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Does anyone have the parts list for the unwink buffered jtag?

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[edz]

Does anyone have the parts list for the unwink buffered jtag?

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Hope this helps.......

Parts list:

(10) 100 ohm resistors (1/4 watt). Digi-Key part number 100QBK-ND
(4) 2.2K ohm resistors (1/4 watt). Digi-Key part number 2.2KQBK-ND
(1) 74HCT244 IC. Digi-Key part number MM74HCT244N-ND
If you're searching through a local shop and they don't have the exact part number, some other familys of the 74_244 chip may work. It does still need to be a 74_244. Other 74_XXX chips will not work. Avoid 74LS244 chips. The LS stands for "Low power Schottky" They won't work across the full voltage range of some parallel ports. Thanks go out to several people for setting me straight on that one. I've also been told that the 74F244 is probably an even better part.
(1) 25 pin Male parallel port connector (DB25). Digi-Key part number 225M-ND
You will want to get the style with the wirecups so it fits over the edge of the pcb. The through hole part won't work with this layout.
(1) Ribbon Cable. Digi-Key Part number R001-5-ND (14 conductor)
You need less than a foot of cable total, so you will have some excess.
(1) 20 pin IC socket. Digi-Key part number A9420-ND
(1)Male header strip. Digi-Key part number 929836-09-36-ND (72pin cut to fit) or WM6914-ND (14 pin)
This is mainly for a quick disconnect setup so you can use the same jtag for multiple receivers. Also the finished job looks cleaner with one of these installed in the receiver. The layout for making your own pcb will not accept a header. Its just too difficult to make a home brew pcb come out with traces that close together.
(1) Press on connector.Digikey part # MSC-14K-ND is for a 14 contact connector.
This part clips permanently onto a ribbon cable and then presses temporarily on to the header strip. It makes it easy to attach and detach your jtag from your receiver so you can use the same jtag in multiple receivers.
(1) Battery holder. DigiKey Part # SBH-331AS-ND (takes 3AA batterys)
If you don't want to leave the jtag installed into the reciever permanently, you will need to power it from somwhere. It can be done from inside the receiver, but you have to run extra wires to do it that way. By adding a battery pack to you can cut down the number of points you have to solder inside the reciever by one or two.

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Thanks for the reply. I am just trying to get this damn thing working with my bev 3100-010 receiver and won't work.

Though maybe it might be the but its not.

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[edz]

I am also having trouble getting my to work with dish net 301.013 , I have another one coming soon ( jtag ) that I am going to try. I'll post back how it gos , but its going to be about a week be 4 I have the new one.

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Here it is I just made it exactly the same way. I downloaded from somewhere. Went & got the parts from radio shack. I never had any luck with it. Im using it on my rca drd420re. It keeps giving me a different device id# during detection. I also cant get a device name either. Has anyone else made this or had any luck with it. Its the first time I uploaded on this sight. I hope the files here & not in adobe reader format. Thats how I viewed it on my computer

Thanks. I managed to find my plans a while ago. I will attach them if you want to try them out. The only difference (other than the power supply switching) is the chip I used is a different version. I heard that some don't work as well and that the one I used was the best for this application. (credit to unwink)

What device ID's is it giving you? Did you try different versions of jkeys?

Did you keep the jtag to receiver lines as short as possible? Are you using a short parallel cable? Have you checked to make sure you are getting proper voltage to your flash chip? Just thinking that the power supply might not be constant. I run my jtag off a variable power supply that way I can easily change between 3.3 and 5 volts for the different receivers that I have worked on.

Just throwing ideas out there.

[FreshManDTV]

Did you check every points of the parallel cable (ie: 19-15 to GND)? If I was you, I'd verify every single point on the DB25.

I use DB25 male ports (those connected to the motherboard on older AT computers) which has ribbon about 3" long, and use a pass-through cable (parallel scanner cable) which is 4 feet long. Between the IRD and JTAG length is about 7". I have good connection every time.

[borg1]

Thank you very much for posting unwink's instruction sheet. I have not used mine in 3 years and had lost the sheet. Without it I would have the world's smallest doorstop.

[smithers]

I have built several buffered jtags. I have found that for the 301's I need to use 4.5 volts instead of 3 volts. Does your jtag have a variable battery power supply?

[borg1]

I last used mine to JTAG a 430RG and soldered to a power pad on the board. I was just searching to see whether I needed 3.3 or 5 volts. I hope it is in one of our old posts. Then I have to find where to get that voltage on a Pantec Ultra. I am reviving a dead one for a buddy at work.

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I use a variable power supply with mine. I run anywhere from 3 to 5 volts.
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