Integer storage in ERAM

KenHorse · Joined: 16 Jul 2004 Posts: 523

So how is it done? For example, I know if I store "-3" in ERAM, it is stored as 2 bytes of 253 and 255 decimal.

My problem is I'm trying to convert those 2 bytes back to an integer in a VB program but it only seems to work for positive numbers. If a negative (as above) is stored, my VB code isn't happy at all.

I know this is a VB issue but knowing what to look for in ERAM would certainly help!

(BASCOM-AVR version : 2.0.7.7 )

albertsm · Joined: 09 Apr 2004 Posts: 5920 Location: Holland

your VB is probably using longs and not integers ?
make a simple program, then watch the values in the Simulator. eram data is stored the same as sram data. LSB first.

you can do the same for your VB code. But you need to use something like peek() to get the memory position. My guess is that your VB code is storing integers as longs.
In such a case you need to check the sign bit (bit 15). and when it is set, make all leading bytes 255.

AdrianJ · Joined: 16 Jan 2006 Posts: 2483 Location: Queensland

Integer storage in VB is the same as in Bascom. So if you declare a variable as integer in VB, it will be rendered correctly, ie bytes stored as 253, 255 will render as "-3".

How are you actually storing the bytes you read from eram so VB can see them ?

KenHorse · Joined: 16 Jul 2004 Posts: 523

The integer is dimensioned as an eram integer and assigned a value.

I have since received a suggestion from a VB forum on how to fix my VB code, which I did. And all seems ok now. Thanks you guys for your inputs![/code]