embeded/ARM2010.05.03 01:04
암용 JTAG 중에 자작가능한 것으로 Wiggler 라는 녀석이 있다.
eleparts에서 완제품 팔기도 하고, 회로도 구해서 만들수도 있다.
예전에 주워온 PalmPalm 보드에서 지원가능한지는 모르겠다.

아무튼 74AC244 칩이 핵심인듯
그러고 보니.. AVR에는 74HC244인데 호환이 되려나?


[링크 : http://www.eleparts.co.kr/front/productdetail.php?productcode=017023007001000006&sort=]


[링크 : http://www.frozeneskimo.com/electronics/arm-tutorials/jtag-wiggler-clone/]

검색을 해보니
74HC/HCT vs.74AC/ACT

"AC / ACT stands for Advanced CMOS Logic (ACL for short).
 HC / HCT stands for High-speed CMOS Logic (HCL).

The AC and ACT subfamilies are faster than the HC and HCT subfamilies, and draw some more power in some circuits. All chips in the AC* subfamily have lower output resistance than HC* and can sink and source 24 mA at logic levels and up 70 mA (typ) per gate for motor loads. As a result AC* gates can handle more than twice the current of HC* gates (50 - 70 mA vs. 24 mA). Note, though, that while most HC* chips have a 25 mA limit, the HC* driver chips such as the 74HC240 and the 74HC245 (i.e., buffers) can handle 35 mA per device, and a maximum of 75 mA per chip.

The AC & ACT families also draw about twice as much current as the HC & HCT chips (but we speaking here of microamps, so it's usually not a huge deal).

It is occasionally possible to find (high quality) motors that you can drive directly from an HC chip. For intermittent operation, such as you get with a quadcore, you COULD drive very efficient (i.e., very low-current) motors directly. You would definitely need a capacitor (say 0.47 uF) across each motor to keep the noise under control.

[링크 : http://www.extremetesting.tv/forums/showthread.php?t=16755]

머.. 결론은 It works! 라는데.. 흐음..

아래 문서에는 74HC244로 되어있다.
[링크 : http://files.tomek.cedro.info/electronics/doc/jtag/doc/openocd_preliminary_20060102.pdf]

아무튼, PalmPalm은 PXA255 칩이고 이녀석은 ARMv5TE 계열이고 Intel XScale 인데
[링크 : http://en.wikipedia.org/wiki/XScale]

일단은 Wiggler에서 지원하니 Wiggler 호환에서도 되지 않을려나?
[링크 : http://www.macraigor.com/cpus.htm]
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Posted by 구차니

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