JTAG and state machines

[Andrew Dawson]

Can anyone help with a problem I have come across in my current
design. The design contains a number of state machines, with the
states declared as follows:

TYPE state_type IS (idle, transfer, wait_2, wait_6, strobe, end_6,
end_2, cycle);
..
..
VARIABLE state: state_type;

This works fine for standard state machine operations, but I have been
unable to find an easy way of incorporating the registers generated
for these types into the JTAG scan chain.

The following statements can be used to assign numerical values to
particular states, but these numeric values only seem to be used in
synthesis, and can't be used interchangably with the named state
values.

ATTRIBUTE enum_encoding: string;
ATTRIBUTE enum_encoding OF state_type: TYPE IS "000 001 010 011 100
101 110 111";

Is anyone aware of a simple way to assign both a numeric and text name
to a variable?

--
Andrew Dawson, Design Engineer
Acorn Risc Technologies Tel: +44 (0) 1223 725259
Acorn House, 645 Newmarket Road Fax: +44 (0) 1223 725901
Cambridge, CB5 8PB, United Kingdom