CV 29 Check Bit 4

[Chrissaf]

Pete, I'll take your feedback on board for version 3 i.e definition of a Byte ....plus I'll see if I can add a bit more descriptive text around table 1.

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Do I take it, your physical location is Paris, if native French, your written English is very good, or are you ex-pat? Sorry for being nosey!

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In answer to your other points of clarification.

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Yes, Bits 7 to 0 = 8 bits = 1 Byte

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Some of the terminology has developed over years.

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Go back to the 70's and personal computing, I'm thinking pre ZX Spectrum and the like here, were 8 bit machines, over time machines got faster and got more memory, and moving chunks of data around in 8 bit chunks was too slow. So along came 16 bit computer architecture, followed by 32 bits followed by 64 bits. The higher the number of bits that could be transferred the faster the computer architecture becomes, and more importantly the size of the amount of memory that can be addressed.

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So that's the background basics with regard to bits. So the boffins doing all this computer development developed terminology that related to bits.

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• 1 bit = a Bit
• 4 bits = a Nibble
• 8 bits = a Byte (but on an 8 bit machine a Byte can also be a Word, but not really relevant to modern computing)
• 16 bits, 32 bits or 64 bits = a Word ( Word term is still used generically even though the number of bits in it depend upon the computing architecture).

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Then there are other terms like Octet, Hex (Hexadecimal) and others that are not worth going into here as not relevant to DCC CVs. But what I will say is Hex is an interesting maths concept, a 8 bit Byte can be represented by just TWO characters. You might come across something called a MAC address (Media Access Control). MAC addresses are written in Hex.

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There was a time, many moons ago, when I could translate numbers in all these different formats in my head. A couple I can still remember like Decimal 255 = FF in Hex for example. But I'm going off at a tangent, time for me to shut up and be quiet. Or more importantly go to bed, its 02:20 Am UK time here at present and still not feeling tired yet.

 

[Flashbang]

Chris, Can you message me directly via my web site please, as I need to speak to you.  Thanks.

[Chrissaf]

Done

[Chrissaf]

@Pete172

Pete, please find my issue 3 tutorial link below. I have taken on board your comments with regard to Table 1 and revised the first section of the document to include significant additional detail in line with what you requested.

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@St1ngr4y

Ray, I have now included a section on your 'divide by 2' method. I found a way to document the process in text in a format that I was happy with. Hope you are too.

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@Flashbang

I have been on what I believe to be your site (B.L) and filled in your on-line contact form as per your request to me. At time of writing this, I have not as yet seen an incoming message in my mail box. I did however receive an 'automated acknowledgement mail' from your web site server.

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CV Bits Tutorial v3.PDF

 

 

[96RAF]

@chris

flashbang aka Brian Lambert according to google

you learn something new every day.

[Chrissaf]

Rob, thus my cryptic reference to B.L. This came to light on the forum about a month ago, probably missed by most, but I have eagle eyes.....Intrigued by what he wants to talk to me about in private....time will tell.

[Flashbang]

Reply sent - Thanks for making contact.

[Pete172]

 Hi Chris,

You asked -" Do I take it, your physical location is Paris, if native French, your written English is very good, or are you ex-pat? Sorry for being nosey! " ....no I'm only 1/2 French and living in Scotland, but feeling rather connected to my other half when I hear of what happened in Paris, approx 89 teenagers systematically shot dead in cold blood in that theatre !, plus all the other deaths of decent people dining out, makes my blood boil.

However,back to railways, I thought your tutorial was very good and got my brain working again, I vaguely remember being taught the basics of Denary & Binary in primary school 50 yrs ago !, but obviously have forgotten most of it since then.

I've not had a chance to look at your latest revision of the tutorial, but I will tomorrow - thanks.

Bits, Nibbles, Bytes - was this terminology devised by the Americans per chance ?.

 

Before I go, any chance of a brief explanation of speed steps, I understand the concept of 128 steps in the speed range, in the LokSound V4 decoder manual it says, e.g "Synchronising Steam Chuffs "in chapter 13.4 - "put the loco on the track and drive it with speed step 1 then use a stop watch to measure time to cover distance "etc... but how can I tell if my loco is travelling at speed step 1, or any other speed step for that matter ? using Elite + Railmaster.

Thanks again.

Peter...

[96RAF]

@Pete

Speed steps - in RM settings untick the box for Scale Speeds temporarily while you do your tests.

You see at the top of the throttle slider a pink box with the speed step set 0-127.

Once you have finished tick the scale speed box in settings again and the slider box will go green and indicate scale speed instead.

Thanks to Yelrow for pointing out this hidden detail a while back.

[Pete172]

 Hi Magfan, & RAF,

Thanks for your help about speed steps, suppose it would be good if the Elite gave some feedback indication of the speed step in the display window ?

CV29 is an area I have not ventured into ..yet..but if you can let me know about CV 29/and what Railmaster can do ?

thanks,

Peter

 

[96RAF]

@Pete

Elite control knob is rate defendant - i.e. the faster you turn it the more it throttles up. If you turn it very slowly it never throttles at all. So it would be difficult to get an accurate speed step you have sent to the loco indication on it.

For really accurate speed step indication when testing I use Rocrail. The throttle is spot on for speed step testing, I have mine such that one mouse wheel roll notch equals one speed step. Its free to download, works with the Elite and is easy to set up for a quick trial - the sample trackplan will let you set up the loco for test.

[Fishmanoz]

I know it doesn't say this anywhere and I could be entirely wrong but I've always assumed that each ray shown on the Elite display was one speed step. What do others think?

 

Also, speed step 1 is not the speed at which the loco starts to move unless you set the Starting Voltage CV to make it so.  Without doing this, the loco may not start to move until step 5 or 6, typically.  Then others may start moving at 1, it depends on a whole lot of electrical and mechanical factors.

 

And to learn about CV29, go to the earlier pages in this thread, heaps in here on it, more than you'll ever need in fact.