JTAG Wiggler question

Development Boards MicroMod
1

Hello, im trying to figure something out. Im kind of new to arm and want to make a wiggler clone:

http://www.frozeneskimo.com/electronics … ler-clone/

I found that and i know i tried it before with success. What i want to know is on Olimex boards they include all debug pins like:

http://www.olimex.com/dev/images/arm-jtag-layout.gif

but on the wiggle clone it only uses:

TDI,TMS,TCK,TDO,RST ,GND,VCC

Is it safe to assume thats all i need when developing a board of my own? Like if i want to make it have a 2x5 (10pin) header. And not use the 2x10(20pin) header.

Can i omit the other lines like:

Where – is removed :

–VREF,–NTRST,TDI,TMS,TCK,–RTCK,TDO,RST ,–DBGRQ,–DBGACK,GND,VCC

to create: TDI,TMS,TCK,TDO,RST ,GND,VCC

Will i still be able to debug and stuff? I plan to mainly use a LPC2103

2

Those are all the signals that are needed. I’ve got a Wiggler clone design in the Files section of the Yahoo LPC2000 group that works very well, it’s much faster than a genuine Wiggler because I designed the PCB properly!

3

leon_heller:
Those are all the signals that are needed. I’ve got a Wiggler clone design in the Files section of the Yahoo LPC2000 group that works very well, it’s much faster than a genuine Wiggler because I designed the PCB properly!

Ill check it out thanks! I forgot about that group. Ive been registered for a while too…

This one right?

application/zip jtag.zip

JTAG interface

4

Take a look here. I posted my schematics. If you got time can you take a look and tell me if any errors appear to you.

http://atomsoft.wordpress.com/2010/09/2 … dev-board/

5

The standard JTAG connector has 20 pins.

I think that is my design. Check your schematic against my LPC2106 design. It includes the JTAG connections; it was added to the prototyping area as I didn’t put it on the original PCB.

6

leon_heller:
The standard JTAG connector has 20 pins.

I think that is my design. Check your schematic against my LPC2106 design. It includes the JTAG connections; it was added to the prototyping area as I didn’t put it on the original PCB.

Yes you use the standard header but i plan to use a smaller one since so many grounds and power isnt a needed thing.

I will also make a adapter for protoboards … let me post a image:

http://atomsoft.files.wordpress.com/2010/09/adapt.jpg

This will turn my small connection to a full JTAG for other proto-boards.

7

I should have used pullup and pulldown resistors on the JTAG connections, but it worked OK without them. You should include them.

8

leon_heller:
I should have used pullup and pulldown resistors on the JTAG connections, but it worked OK without them. You should include them.

Ill be sure to add them. Ill take the design from the olimex board. And assign pull-up and down resistors appropriately.

UPDATE:

Take a look:

http://atomsoft.files.wordpress.com/2010/09/rev3.png

9

I’ve got a little PCB I made at home for the LPC2103, but I never got round to trying it.

10

leon_heller:
I’ve got a little PCB I made at home for the LPC2103, but I never got round to trying it.

Cool. Sorry my internet connect is real bad this month. I hope they give me a credit for this terrible service.

Anyway, thats cool. How come you never tried it? I finally read some of the datasheet and understand a tiny

bit of how the debug stuff works. Thanks for your help.

11

I’ve got several projects like that that I’ve never finished. Much better ARM boards have come along that are easier to use, and very cheap.

12

Ahh i see ok. Makes sense. I just finished the PCB for my Wiggler. Well the design in eagle. Ill make the PCB itself later on today.

13

one question. On the LPC2103 (and other ARMs) the main debug pins are TMS,TDI,TDO,TCK,TRST

Now i know that. But im not sure if this is a mistake… the TRST (P0.27) isnt used in any wiggler clone. But the RST from the ARM (pin 6) is used… is that normal?

On the Olimex boards i can see the pinout for debug and it uses all the correct pins i assume. But on my wiggler clone and yours leon. The TRST isnt used at all.

What i want to know is… will it still work as long as TRST (P0.27) is pulled up?

14

TRST doesn’t need to be pulled up, and isn’t used by most JTAG interfaces.

15

oh ok had to make sure. Dont want to waste PCBs and parts heh… its a recession you know :smiley:

16

Leon i made the wiggler from:

download/file.php?mode=view&id=607&sid= … 4173dfceb2

But its still a no go. I bought this:

http://www.sparkfun.com/commerce/produc … cts_id=667

But still a no go! Whats up? Attached is my JTAG schematic and Board file. Please tell me whats wrong!

17

Also im trying H-JTAG since i can ensure it using right cable wiring.

I tried inverting and non inverting RST also all divider speeds. in every combo heh. No Luck!

18

I GOT IT!!! DAMN STUPID SCHEMATIC SYMBOL. The transistor was wrong. I repaired and works!

Wrong on mines i mean… yours is perfect… thanks again!!!