Hex converting

[Andre_Pretorius]

i have seted up a modbus link with a exsternal device the problem is now that i get my data in as 4 bytes of hex numbers
eg. 07D9 is what i am getting it must become a year number 2009

any idea's how i can get this conversion
thanks in advance

[Andre_Pretorius]

this is what i have tried so far

DataA=DATAIN(8)
Gosub HEXConvert

The idea is data from the attay is pased to a temp value, a subrotine is called end if the values are bigger than 9 the coresponding digital value is replaced into the temp value, if none of the if statements are true the value are returnd

it still return the same hex caractor - any ideas

HEXConvert:
IF DATAA = $A THEN
	DATAA = 10
	RETURN
ENDIF
IF DATAA = $B THEN
	DATAA = 11
	RETURN
ENDIF
IF DATAA = $C THEN
	DATAA = 12
	RETURN
ENDIF
IF DATAA = $D THEN
	DATAA = 13
	RETURN
ENDIF
IF DATAA = $E THEN
	DATAA = 14
	RETURN
ENDIF
IF DATAA = $F THEN
	DATAA = 15
	RETURN
ENDIF

RETURN

[Melanie]

If you make an assumption firstly that you have valid (UPPERCASE) ASCII HEX and not Klingon or some other alien data... then your ASCII HEX to Numeric conversion could be as simple as...

	DataA=AsciiHexByte-48
	If DataA>9 then DataA=DataA-7

If you need to handle UPPERCASE or lowercase (valid) HEX, then your code needs an extra line...

	DataA=HEXByteInput-48
	If DataA>9 then DataA=DataA-7
	If DataA>15 then DataA=DataA-32

What YOU are doing is NOT converting ASCII HEX... you are converting one form of Number representation to another form of exactly the same number... $A=10 anyway, so what you are doing is stating...

If DataA=$A then DataA=10

... which is the same as...

If DataA=10 then DataA=10

... which is kinda pointless... what you should have said is...

If DataA="A" then DataA=10

... or to be long-winded about it...

If DataA=65 then DataA=10

... because $A=10 whilst "A"=65

[Andre_Pretorius]

Thanks

This is how I hot it working, you were right about the A being 65

HEXConvert:
IF DATAA = 65 THEN
	DATAA = 10
	RETURN
ENDIF
IF DATAA = 66 THEN
	DATAA = 11
	RETURN
ENDIF
IF DATAA = 67 THEN
	DATAA = 12
	RETURN
ENDIF
IF DATAA = 68 THEN
	DATAA = 13
	RETURN
ENDIF
IF DATAA = 69 THEN
	DATAA = 14
	RETURN
ENDIF
IF DATAA = 70 THEN
	DATAA = 15
	RETURN
else
	DATAA = DATAA - 48
ENDIF

RETURN

[Ioannis]

Hmm, some people still like spaggeti much more!

Hope at least there is a good salsa with it...

Ioannis

[ukemigrant]

If you're sure your data really just consists of the digits and letters A through F, use this instead. Including comments will help when you come back to it later too.

' This works because 0 - 9 have decimal codes 48 - 57 and A - F have 
' decimal codes 65 - 70 in ASCII
HEXConvert:
IF DATAA >= 65 THEN
	DATAA = DATAA - 55 ' 65 - 55 = 10, 66 - 55 = 11 etc
else
	DATAA = DATAA - 48 ' 48 - 48 = 0, 49 - 48 = 2 etc
ENDIF

RETURN

http://www.asciitable.com/.

[Andre_Pretorius]

Thank you tried the new code and works like a charm

[aratti]

eg. 07D9 is what i am getting it must become a year number 2009

An algoritm to convert Hex to Dec is as follows:

Hex 07D9 = 9x16^0 + 13x16^1 + 7x16^2 + 0x16^3 = Dec 2009

I don't see how you achieve the convertion with your system!

Al.

[ukemigrant]

An algoritm to convert Hex to Dec is as follows:

Hex 07D9 = 9x16^0 + 13x16^1 + 7x16^2 + 0x16^3 = Dec 2009

I don't see how you achieve the convertion with your system!

Al.

I'm sure he's using the partial algorithm he gave to get the 13 from the D for example and then plugging it into another equation like yours.

[ukemigrant]

If you're sure your data really just consists of the digits and letters A through F, use this instead. Including comments will help when you come back to it later too.

' This works because 0 - 9 have decimal codes 48 - 57 and A - F have 
' decimal codes 65 - 70 in ASCII
HEXConvert:
IF DATAA >= 65 THEN
	DATAA = DATAA - 55 ' 65 - 55 = 10, 66 - 55 = 11 etc
else
	DATAA = DATAA - 48 ' 48 - 48 = 0, 49 - 48 = 2 etc
ENDIF

RETURN

http://www.asciitable.com/.

Of course 49 - 48 <> 2 . Luckily it was in the comments but still...