I knew what that was going to be before I even clicked. Lehrer is great (he's still alive, actually). He should redo New Math to cover the silly stuff they teach today.
But really - indexed CVs just require one bit of knowledge - what CV is the index. After that, the notation isn't in the least confusing. 1. means set the index to 1, 2. means make it 2, etc. Doesn't take much thought, and certainly no calculation.
Hex makes much more sense than octal, and you cna do octal without even using your thumbs. It's why I always hates 8080 assembly - the 8080 instruction set it based on octal, and similar opcodes are grouped together by octal representation, which means in hex, they're all over the place. My first computer, it had only a hex keypad for input. But the CPU it used had its instruction set organized for hex numbering. It helped that it also has 16 registers, more than any other 8 bit CPU of the day. So you might have an opcode to say put a value in a register. It started with A, so A0-AF handled registers 0-15. If the 8080 had that many registers, the opcodes in hex would have been some jumbled mess like A0-A3, then B6-B9, and finally CA-CF or something. Utterly impossible to memorize. Hex perfectly represents an 8 bit byte with exactly 2 digits. Octal overflow - for 0-255, it's 0-377. So you have the high digit only going from 0-3, and the other 2 digits go 0-7. That's confusing. 8 bit bytes do not evenly go into base 8 numbers. You need a 6 bit or a 9 bit computer to be even octal digits. And that's just wrong when the computer naturally deals in binmary. Binary and octal don't get along in nice even numbers, it's groups of 3. Jarring. Binary and decimal don't get along at all. Binary and hex are perfect companions.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinkerPeople are always making this out harder than it has to be. CV257, for example, can refer to 3 different things, The index simply sets which of those 3 things you are referring to. If the option you are trying to configure says it's controlled by CV 2.257, you set CV32=2 and then configure CV257. If the setting is listed as CV 3.264, you set CV32=3 and then set CV264.
There is a song about something very similar to this. After all, don't panic, hexadecimal is just like base 10, if you take off one shoe and have a hole in your pocket...
https://www.youtube.com/watch?v=W6OaYPVueW4
"Basically, [you] should never have to program that one. Just set CV32 to 1, 2, or 3..." Agreed, assuming everything works the way it should. And the manual does say "assure" that CV 31 shows a value of 16. With the Digitrax throttle, it is only one more click of the Left knob to get to CV 32 and the value can then be set with just a few more clicks of the Right knob. "Trust but verify."
Thanks, again, for everyones input and help!!
BigDaddy mvlandsw Once I set CV 31 or 32 to the required value and then program an indexed CV does CV 31 or 32 return automatically to its default value or do have to reset it manually? Mark Vinski I don't think so, because 31 & 32 give you access to write to other CV's they don't alter any function by themselves. York what are you still confused about?
mvlandsw Once I set CV 31 or 32 to the required value and then program an indexed CV does CV 31 or 32 return automatically to its default value or do have to reset it manually? Mark Vinski
I don't think so, because 31 & 32 give you access to write to other CV's they don't alter any function by themselves.
York what are you still confused about?
The Soundtraxx manual specifically cautions you against setting CV31 to anything but its default of 16. Basically, uoi should never have to program that one. Just set CV32 to 1, 2, or 3 depending on which index group, and then you put the actual value in the specific CV, like 254. SO to set CV 2.273 (I'm making this up) to a value of 24, you would do CV32=2 and then CV273=24.
The decoder is new, it's a Tsunami 2. The throttle is a DT500D for the Digitrax system at the club I recently joined.
My entire model rolling stock roster consists of a new Athearn Genesis GP-7 (with the Tsunami decoder & sound), one Accurail boxcar (bought for $15 from another club member) and one MR&T, limited edition, 41' gondola! The "collection" is housed in a Fast Tracks Freight Crate! Not one inch of track (no main, branch nor programming). Not one power source. Not one building. I do still have a room that was originally called "My Layout Room". The room is our 26 yo Grand's Den. Oh, I also have a couple of 40' shipping containers I built from printed Team Track Models pdf's. They are sitting on some club members well car that I think is bad ordered! OTOH, I'm only 77, so what's the rush?!
mvlandswOnce I set CV 31 or 32 to the required value and then program an indexed CV does CV 31 or 32 return automatically to its default value or do have to reset it manually? Mark Vinski
Henry
COB Potomac & Northern
Shenandoah Valley
x-airbusdriver"People are always making this out harder than it has to be." That's me! Guilty as charged! However, I had several good responses that explained
airbusdriver, take comfort in the fact that you at least understand the responses. I'm completely lost in this.
Maybe it's my age.
York1 John
I assume you have a newer Digitrax system, or one with a newer throttle at least - because the older stuff couldn't use more than 255 for a CV number. That was the original DCC spec. Decoders have workarounds for this, which just really means a more complex way of indexing. And Digitrax isn't the only system with this limitation.
JMRI does make this a lot easier - no programming index CVs, just check a box, or adjust a slider, or whatever control is appropriate for the setting, and when writing to the decoder, JMRI sets the index as needed. You just drag the slider for horn volume higher to make it louder and save it. You will need an interface to connect to your computer, unless you have one of the new command stations with USB built in.
Thanks guys!!
"People are always making this out harder than it has to be."
That's me! Guilty as charged! However, I had several good responses that explained the reason I saw the references to "ensure CV 31 is set to 16.". That is step 1 I should have figured out that the first digit, "1", "2" or "3" was being set in the "Page" CV32. That's step 2. The last step (3) is to set the CV with the last three digits (257 - 512). That's probably what the instructions were trying to tell me!
I suspect that the DCC committee of NMRA never thought we'd never need more than 3 digit CV addresses. Perhaps Bill Gates was their chairman?!
Thanks for the wiki link!
x-airbusdriver Probably over-thinking due to under-knowing... I'm using a tsunami decoder while using a Digitrax DCC system at a club layout. I have edited a few CV values successfully, but can't find anyone at the club to confirm my how to program some CV's. The tsunami has many CV's with "1.257 - 1.512", "2.257 - 2.512" and "3..257 - 3.512". The Digitrax throttles (used for programming) have a method for setting CV addresses with either 2 or 4 digits. I am assuming that to edit a CV such as 1.289, I would simply use the 4 digit address setting method. Only thing that makes sense to me, so I would appreciate some conforimation from a human, a referrence to a Manual page number, a thread in these forums or even an MNRA Standards document.
Probably over-thinking due to under-knowing...
I'm using a tsunami decoder while using a Digitrax DCC system at a club layout. I have edited a few CV values successfully, but can't find anyone at the club to confirm my how to program some CV's.
The tsunami has many CV's with "1.257 - 1.512", "2.257 - 2.512" and "3..257 - 3.512". The Digitrax throttles (used for programming) have a method for setting CV addresses with either 2 or 4 digits.
I am assuming that to edit a CV such as 1.289, I would simply use the 4 digit address setting method. Only thing that makes sense to me, so I would appreciate some conforimation from a human, a referrence to a Manual page number, a thread in these forums or even an MNRA Standards document.
Yes, the Indexed CV.
You ave to write values into CV 31 and 32, then the final value you want into another CV.
Software such as JMRI handles this almost transparently, making it much easier than doing it manually.
See https://dccwiki.com/Configuration_Variable#Indexed_CVs for more details. You will need to read the decoder manual and follow the instructions carefully.
Once I set CV 31 or 32 to the required value and then program an indexed CV does CV 31 or 32 return automatically to its default value or do have to reset it manually?
Mark Vinski
Randy beat me
x-airbusdriverI am assuming that to edit a CV such as 1.289, I would simply use the 4 digit address setting method
You are assuming wrong. Neither Loksound or TCS use the convention of referring to any CV as a number with 3 decimal places
These are Indexed CV's. That means you have to know the code to program, for instance, CV 289. The code involves programming CV 31 and 32 to specific values. 1.289, 2.289, 3.289 are the same CV but enable that CV to control different things.
Page 15 of this manual explains it https://soundtraxx.com/content/Reference/Manuals/Tsunami2/tsu2_diesel_usersguide.pdf
Read the section of the Tsunami manual about indexed CVs. It explains where the 1, 2 or 3 goes for 1.257 or 2.257 or 3.257.
Page 31 of the Tsunami 2 Diesel Technical Reference Manual is where you want to look. CV32 is the index CV, that gets set to 1, 2, or 3. Further explanations are on the first page of the section for each index: Page 118 for index 1, Page 123 for index 2, and page 133 for index 3.
Think of a row of 3 file cabinets. Each unit has say 4 drawers, 1-4. You can;t just sya the item you want is in drawer 2, there are a total of 3 draw #2s, one in each stack. You need another coordinate, or an index - row 2, drawer 2 then points to a specific drawer to locate your item.
People are always making this out harder than it has to be. CV257, for example, can refer to 3 different things, The index simply sets which of those 3 things you are referring to. If the option you are trying to configure says it's controlled by CV 2.257, you set CV32=2 and then configure CV257. If the setting is listed as CV 3.264, you set CV32=3 and then set CV264.
The whole reason this exists is because few if any systems can use 4 digit CV numbers. A CV is not the same as the loco address.