Legal syntax for VHDL expression

I am writing a case statement and it doesn't seem to like an attribute
as a selection expression. Is an attribute not a legal item in an
expression?

It flags an error at the "of" on the first line saying 'keyword "is"
expected'
and at the beginning of the last line shown here saying 'keyword "end"
expected'

case LFSRReg'high of
when 2 =
Feedback := Feedback xor LFSRReg(2);
Feedback := Feedback xor LFSRReg(1);
when 3 =

I seem to get rusty on VHDL between projects, but I thought I knew how
to construct a case statement. Am I just getting old?

Rick

On 21/02/10 01:53, rickman wrote:



I am writing a case statement and it doesn't seem to like an attribute
as a selection expression.  Is an attribute not a legal item in an
expression?

It flags an error at the "of" on the first line saying 'keyword "is"
expected'
and at the beginning of the last line shown here saying 'keyword "end"
expected'

     case LFSRReg'high of
           when 2 =
             Feedback := Feedback xor LFSRReg(2);
             Feedback := Feedback xor LFSRReg(1);
           when 3 =

I seem to get rusty on VHDL between projects, but I thought I knew how
to construct a case statement.  Am I just getting old?

Rick

The syntax is
  case expression is

so replace "of" by "is",

regards
Alan

--
Alan Fitch