Binary to float or some thing?

[Tom-H-PIC]

I'm not the sharpest tool in the shed when it comes to math but I'm not that a total idiot either.
I'm working with the Cirrus Logic CS5463 Power IC and a PIC18F4550.
Ok the issues is the data coming back from the CS5463 I don’t understand how to convert it to some thing useable like a float or an int32.
All ADC that I have worked with have a bit weight so the returned value is multiplied by this bit weight and you have your number.
I don’t understand the data sheet explanation of the returned data from this CS5463.
The full data sheet is located at this link.
http://www.cirrus.com/en/pubs/proDatasheet/CS5463_F1.pdf

The page and items that I'm look for help on are on page 28, RMS current & voltage register.

[img]http://pg.photos.yahoo.com/ph/troncam/detail?.dir=fea6re2&.dnm=5bb8re2.jpg&.src=ph[/img]

(Sorry i can not make the img thing work. how do you get and img in a post?)

I don’t understand the Epsilon register at all is this a float? It looks kind like a float format but I don’t think that I see the whole picture.
Also the voltage and current RMS confuse me also.
Any help that any one can give would be extremely appreciated.
Thanks all
Tom

[newguy]

The RMS V and I register is simply read - no scaling. The number is built as follows:

The MSB is defined as 2^-1, or one half (1/2). The next bit (going right) is 2^-2, or one quarter (1/4). The next one represesents 1/8, 1/16, 1/32, etc until the LSB, which is 2^-24 = 59.6 x 10^-9. The data sheet also states that this register can have values ranging from 0 to <1.

So if the RMS I was 0, this register would be all 0's. If it was 0.5A, the register would contain 0x80 00 00. If it was 0.375A, it would contain 0x60 00 00 (= 1/4 plus 1/8). And so on and so on and so on. If all bits were set, 0xFF FF FF, the measured current/voltage would be 0.999999999A.

The easiest way to deal with these values in a PIC would be to store them as unsigned int32's. Then scale as appropriate by noting that 0x01 00 00 00 = 1 amp/volt.

The epsilon register is similar, but it can range from -1 to < 1. The MSB in this register is the sign bit - if it's a 1, then the number is negative. I don't get why this register can hold negative numbers when the datasheet states that "negative values have no significance."

Hope this helps.

[Tom-H-PIC]

Thank you for the help.
Yes the Espilon register statement threw me for a loop also.
I don't have any idea why it is that way or the total understanding of that statement.
And again thanks for taking the time to look at it.
Tom

[Sarada]

Dear Sir I am using CS5463 with PIC 18f4550 i am able to get 3 bytes of data the MSB is -(2^0) then 2^-1 --------to 2^-23 please help me on Conversion and how to get current and voltage readings in Decimal format eg.230V and 5A . awaiting for you reply.