Asian shares edged up on Friday and gold slipped ahead of a speech by Federal Reserve Chairman Ben Bernanke on the U.S. economic outlook later in the day, while the euro gained after Spain agreed on a constitutional debt brake.

European shares are seen opening flat to lower, ahead of the speech, according to financial bookmakers.

S&P 500 futures rose 0.4 percent during Asian trading hours, pointing to slight gains in Western markets later.

Stocks on Wall Street fell on Thursday as investors lowered their expectations that Bernanke, who is due to address central bankers at an annual symposium in Jackson Hole, Wyoming, at about 10 a.m. EDT on Friday will announce drastic measures to kickstart growth in the world's top economy.

His speech last year laid the groundwork for the Fed's $600 billion bond-buying program to revive the economy under the rubric QE2 for the Fed's second round of stimulus, or quantitative easing.

While investors have speculated Bernanke could signal a new monetary offensive in his talk, many analysts say he could well disappoint those looking for major measures, such as a QE3.

The market is lacking upside potential as some doubt there will be another round of quantitative easing from the Fed, said Lee Suk-won, a market strategist at E-Trade Securities.

Investors are also looking out for the U.S. government's preliminary estimate for June-quarter economic growth before Bernanke's speech on Friday.

The MSCI world equity index edged up 0.1 percent, taking its gains this week to almost 2 percent, which recovers only a fraction of the steep 16 percent loss it suffered over the four previous weeks.

Asian stocks flip-flopped on Friday, with the Nikkei 225 index closing up 0.29 percent at 1:30 a.m. EDT, while the broader MSCI Asia Pacific ex-Japan index gained 0.1 percent.

While there is speculation that there may not be a clear indication of QE3 from Bernanke, investors do not want to take positions, said Yutaka Miura, a senior technical analyst at Mizuho Securities.

The Australian dollar rose 0.5 percent against the U.S. dollar after cautiously upbeat comments by Australia's top central banker pointed to lower risks of deep interest rates cuts.

The Euro rose against the U.S. dollar to $1.4427, boosted by an agreement between Spain's government and opposition parties to enshrine caps on public debt in the country's constitution.

Brent crude was flat at $110.60 per barrel ahead of the Bernanke speech, with sentiment supported by worries about Hurricane Irene's impact U.S. East Coast supplies.

Gold rose 0.5 percent to $1,778.6, but the precious metal is still on track for a weekly loss of almost 4 percent, its first after seven straight weeks of gains as investors rushed into the safe haven during unprecedented market turmoil.

(Additional reporting by Ju-min Park; in Seoul and Ayai Tomisawa in Tokyo; Editing by Daniel Magnowski)