Nikon coolpix 3200 JTAG the firmware to this brick

During firmware upgrade, battery is drained out suddenly then....the lovely Nikon Coolpix 3200 is no longer turn on again, this was a long story about in March of 2008.

What to do, set this brick apart to look at what is fun to deal with, more or less, disorder those screws, flex cables and so on, except to the known of something about compact design, IC part number, nothing could be done.

In this May of 2009, someone send me an ACTEL chip and looking for the secreat inside the chip. Quickly reviewed the data sheet of which is available at the manufacturer website, and also further reading some application note & product leaflet, of course, it is not easy but possible only after enough investment both for hardware and time, it may say 100 years, who knows.

Up on such event and it triggered myself wanna to know the specific detail of JTAG, yes, JTAG, long enough heard that since 2002 as reading paper of Motorola MCU, what else since then? nothing because I am not the professional.

http://blog.kangkang.org/index.php/archives/183
This blog is giving a very straight forward to know when JTAG was only a word in my knowing, quote as following,

小知识: 什么是 JTAG 以及为什么可以用 JTAG 来修复变砖的电子设备

网上搜索 JTAG，通常能找到的叫法是 Joint Test Action
Group，是个规范。为啥能用来修复电子设备则很少有人讲清楚。简单的说，JTAG
就是一个芯片的后门规范，通过简单的电气接口可以命令芯片做任何它应该能做事情，包括运行任何指令。这个接口本来是为了测试芯片方便的，当然对于
firmware 损坏的电子设备，可以通过命令 CPU 执行指令来刷写 flash，从而达到修复变砖电子设备的目的。

google for some more basic of JTAG
http://zh.wikipedia.org/wiki/JTAG

follow the wiki link above, found the freeware for JTAG, it is possible
for flash memory read & write, but what about the hardware?
http://sourceforge.net/project/downloading.php?group_id=193266&filename=urjtag-0.10.exe&a=91300913

Another simple hardware of LPT port mapping the JTAG pins, it is firmware modding for routers, but can be used for reference,
http://oldwiki.openwrt.org/OpenWrtDocs(2f)Customizing(2f)Hardware(2f)JTAG_Cable.html

the image followings are direct copy from the link above for quick look here

it says the JTAG-to-LPT mapping

 TDI  -  DATA0   - pin 2
 TDO  -  SELECT  - pin 13
 TMS  -  DATA2   - pin 4
 TCK  -  DATA1   - pin 3

base on the existing of LPT, 5V I/O operation is possible by this very simple JTAG interface.

the images of two followings are direct copy from the link above for quick look here

JTAG-to-LPT mapping

 TDI   - DATA3   - pin 5
 TDO   - BUSY    - pin 11
 TMS   - DATA1   - pin 3
 TCK   - DATA2   - pin 4
 nSRST - DATA0   - pin 2
 nTRST - DATA4   - pin 6

base on this circuit diagram, a +3.3V I/O operation is presented by voltage divider of which is powered from the 5V of LPT port.

The next is about the functional block of such camera, in order to access or program the flash, a basic understanding to what CPU is used for the control unit, JTAG is only a door existed to communicate to the CPU, need to know how to talk to the CPU. can not find anything about the coolpix 3200, but a service manual of coolpix 4300 is existed for download as below,
http://www.eserviceinfo.com/downloadsm/20594/Nikon_Coolpix%204300.html

it is not exact to fit the need, but at least a reference could be used to know what looks like by design.

There is another reference to know the basic function of every IC component inside a coolpix, again, reference only as it is for coolpix 4300, not exact the this bricked coolpix 3200.
http://www2.electronicproducts.com/Nikon_Coolpix_4300_Digital_Camera-whatsinside-40.aspx