Apple's afternoon product announcements should be the highlight Tuesday as analysts and gadget geeks eagerly await the unveiling of a new handset and possibly a wearable device.
The euro continued its decline, falling below 1.29 Monday after the European Central Bank last week announced new stimulus and rate cuts. The British pound fell more than 2 percent on fears that Scotland will vote to separate from the United Kingdom. Stocks were mixed with the Dow off 25 points at 17,111, and the S&P 500 off 6 points at 2,001, but Nasdaq closed higher at 4,592.
Oil, falling as the dollar rises, was also weaker after disappointing Chinese trade data, and Brent crude fell through $100 for the first time since June 2013.
Read MoreChoking onoversupply, oil may fall another 10%
Apple, meanwhile, is widely expected to launch two new iPhones and possibly an iWatch at its 1 p.m. EST event Tuesday.
Apple stock has fallen 4 percent ahead of its announcement in the past week. Bernstein Research senior analyst Toni Sacconaghi said the stock usually has significantly outperformed ahead of new iPhone launches and then modestly underperforms afterward. Apple stock fell on four of seven iPhone announcements.
Read MoreThis is what Apple shares do after new products
"While the historical playbook suggests trimming positions now, we believe that the possibility of an iWatch launch (either coincident with the iPhone launch or thereafter) and a payments solution make the decision more difficult this time," he wrote.
Sacconaghi noted that there's potential for Apple to have a "very significant product cycle over the next several quarters," but in the longer term the increasing maturity of Apple's high end smartphone and tablet markets will make it "challenging for Apple to deliver sustained revenue and EPS growth."
Read MoreWhy stocks may keep chugging higher: Floor trader
What to Watch
There is the NFIB small business survey at 7:30 a.m. and JOLTs, the July report on labor turnover and hiring is released at 10 a.m. The Fed watches the JOLTs data, and after Friday's weak employment report, traders will also be more focused on what the JOLTs report says.
Earnings are expected from HD Supply, Barnes and Noble, and Burlington Stores before the bell. Krispy Kreme and Palo Alto Networks reports after the close.
There is a 1 p.m. 3-year note auction.
Correction: An earlier version of this story misstated the dates of the U.S. Federal Reserve meeting.
—By CNBC's Patti Domm.