help clip file extension in bash

any hints / help will be appreciated!!

I'm working in a bash script

I have a file name (e.g.) message.txt.asc

I need to get the plaintext name: message.txt

For some reason I cant get the parameter expansion to work:

TXTNM="${$1%.asc}"

this should result in name for the plaintext as message.txt

i think I've got it now:

TXTNM="${1%.*}"

but I can't see where I've gone wrong