In the run-up to the big final against Cardiff City, the trophy spent yesterday morning at Sainsbury's in Farlington.
Customers had their picture taken with the cup and donated money to the trust, set up in memory of a young Pompey fan who died of bone cancer at the age of 15.
The store held a variety of other events throughout the day, including a football game for customers to play and competitions.
The FA Cup today went to raise funds for three local charities as it pitches into University of Portsmouth Students Union between 1.30pm and 4.30pm.
President Elle Gray said: 'We do a lot of work for OAPs and disabled children so we have decided to offer some of the kids access to the Cup.
'It's important the cup has come to Portsmouth.
'It's amazing Pompey are through.
'We have never had anything like this at the Students Union before.
'It's like an Olympic torch, it comes with minders and you're allowed to touch it but not to hold it.'
The cup will reach new heights on Monday at the top of the Spinnaker Tower, as the clock counts down to the big Wembley final.
It will be paraded in front of fans on the podium area of the iconic tower between 3pm and 7pm.
Pompey supporters will get the opportunity to have their photograph taken with it if they bring along their own cameras.
Tower marketing manager Heather Deeley said: 'It's the first time in almost 70 years that Portsmouth has been in the FA Cup final so it is a proud time.'