convert hex to decimal in PurePath Studio

Kevin Chang2

I used I2C memory tool in GDE to read the data stored in AIC3256 registers. However, the data format is in hex. How do I convert it into decimal value?

In the help of "spectrum analyzer" component, the example convert 0xE70000 into decimal value of -1638400. I cannot understand how it comes from.

Thank you for your help.

Kevin

over 9 years ago

0 Converter Apps over 9 years ago

TI__Mastermind 28585 points

Hi Kevin,

I have asked my colleague to take a look.

Best Regards,

dave

0 Kevin Chang2 over 9 years ago in reply to Converter Apps

Prodigy 230 points

Hi Dave,

Could you remind your colleague take a look for me? Thank you.

My observation is even though spectrum analyzer of GDE outputs 8 digits from I2C memory tool, only the first 6 digit are useful. So adding "FF" in front of that 6 digits, then converting the hex to decimal will be the answer.

Is it correct?

Kevin

0 J- over 9 years ago

TI__Mastermind 46195 points

Hi Kevin,

We have a wiki page explaining this: http://e2e.ti.com/support/data_converters/audio_converters/w/design_notes/2788.converting-from-linear-or-db-values-into-hex-values.aspx

Hope this helps!

J-

0 Kevin Chang2 over 9 years ago in reply to J-

Prodigy 230 points

Hi J,

This page well explains the method of converting decimal to hex for 2.xx format.

However, for spectrum analyzer which uses 7.x format (see the help in attachment), I still don't understand how to convert the 0xE70000 (hex) to -1638400 (decimal) as listed in the example of spectrum analyzer help because 0xE70000 is smaller than the most negative number 0x800000. Perhaps spectrum analyzer uses different converting method? Thank you.

Kevin

7607.Spectrum Analyzer Help.pdf

0 J- over 9 years ago in reply to Kevin Chang2

TI__Mastermind 46195 points

Kevin,

I have updated the wiki article to include conversion back to linear.

In your case:

Value = HEX2DEC(FFFFE70000) / 2^24-7 = -12.5 dB

If you use Excel, you must enter a 5 byte number with leading 1's when working with negative numbers as shown above.

There is no need to convert from linear to dB since the dB conversion is done automatically by the spectrum analyzer algorithm.

If you were to convert an int24 from 0xE70000 to linear, it should yield -1638400. However, you usually only see int8, int16 and int32 in C++, so in you would need to left justify your data to int32 (0xE7000000) and convert assuming 7.25 format. In a C++ program you would need to shift ('>>') by 25 instead of 17 when using 32-bit numbers to get the final dB result. Note that you may need to store the final value as double if you want fractional numbers.

Regards,

J-

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convert hex to decimal in PurePath Studio