Dollar edged down on Friday ahead of a speech by Fed Chair Janet Yellen in Jackson Hole, Wyoming, at which she will speak up her mind about interest rates and the future of monetary policy.

The dollar index, gauging the greenback's performance against a basket of six major currencies, fell 0.10% to trade at 94.61, while the dollar fell 0.12% versus sterling to hover around 1.3209.

Oil prices also gave up ground as hopes are lost for a global deal to freeze production, with Brent crude futures down 43 cents, or 0.87% to hover around $49.23 a barrel, while U.S. crude futures slid 20 cents, or 0.40% to $47.14 a barrel.

Safe havens on the other hand received a boost from the jittery market, with gold futures up four dollars, or 0.31% to $1,328 an ounce, while silver prices climbed 13 cents, or 0.70% to trade at $18.61 an ounce.

Traders await some U.S. data later today, with the second reading on GDP growth expected to show a growth of 1.1% q/q in the second quarter, down from 1.2% in the first reading.

A survey tracking consumer confidence is forecast to show a slight uptick to 90.6 in August from Jule's 90.4, which could underpin the dollar.