I2C NXT block modifications / new block supporting RS485 interface port 4

Question

Hello
1. Has anyone tried to modify the published I2C  read and write NXT blocks so that they can support the full 16 byte buffers available in the NXT firmware.  Many I2C interface applications require more than reading or writing one byte at a time.
Even the Ultrasonic sensor has some multi byte parameters that could be accessed.
It would appear that one only has to provide access to the buffer element contained within the lower level VI's in the current solution, but being a newbie   i have not been able to successfully make these buffers available on the main front panel.
2. Has anyone created a NXT block that allows access to the RS485  port 4 hardware.  I see that no one had responded to an earlier post concerning this solution. I have seen  example  NXC code,  but i was looking for an NXT block implementation.
3. Is there a tutorial that explains technique's for developing and debugging a NXT block for use on the NXT ?
I have read thru the pdf  tech docs and have followed the examples, but i still find it difficult to understand how one goes about createing, testing, debugging the application before creating a block for the NXT.
I am obviously missing some important points about Labview development for NXT.  I have a lot of experience developing embedded applications with C, but this is the first time i have tried to do anything with Labview especially with the Lego NXT as the Target device.
I want to create NXT blocks for some homebrew sensors that i have created. I need full access to the I2C and RS485 support in the NXT.
Can anyone suggest ways one should go about createing, debugging, this type of sensor interface block for the NXT.
Thanks
KC

Answer 1

Yes: there are so many questions in your post that it is difficult to build an answer...
I surely can not help you with the problem of multiple bytes.
This is an answer to your question about rs485 in NXT-G:
http://forums.nxtasy.org/index.php?s=&showtopic=1676&view=findpost&p=13530
I don't know if you have already studied the i2c-related pages in:
http://www.tau.ac.il/~stoledo/lego/
this too is an example which can be study both for i2c interfacing and NXT-G block preparation:
http://www.extremenxt.com/tda8444.html
finally the block from mindsensors' PCF8574-NX kit could be useful (I mean: look at the vi's):
http://www.mindsensors.com/index.php?module=documents&JAS_DocumentManager_op=viewDocument&JAS_Document_id=37
and maybe among the blocks they've prepared for their sensors:
http://www.mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=45&MMN_position=12:12
you could learn something.
I agree with you that the tutorial about building NXT-G blocks with Labview is too short;
some lessons can be learnt from the NXT-G blocks done by others (spying the vi's they wrote): you find many of them in nxtasy.org repository.
Some advanced techniques are reported in
http://nxtasy.org/2007/04/12/advanced-nxt-g-block-techniques-part-iv/
and other pages of nxtasy.org.