* Futures down: Dow 0.4 pct, S&P 0.45 pct, Nasdaq 0.54 pct
By Amy Caren Daniel
Aug 10 (Reuters) - U.S. stock index futures fell about half a percent on Friday, tracking global shares, as the Turkish lira tumbled on concerns over the country's economy and its deepening rift with the United States.
The moves in the currency market set a cautious tone on Wall Street, with 18 of the 25 most active stocks slipping into the red in premarket trading.
The dollar rose to a 13-month high against a basket of currencies also driven by rising trade tensions between Russia and the United States.
"Problems in emerging markets are more important than ever because of the global growth engine that emerging markets have become," Peter Cecchini, chief market strategist at Cantor Fitzgerald in New York, wrote in a note.
"This will eventually matter greatly to U.S. markets."
Investors are also keeping a close watch on inflation numbers to gauge the impact of tariffs on pricing and for clues on the path of interest rate hikes.
Data from U.S. Labor Department is expected to show that the consumer price index rose 0.2 percent in July, after rising 0.1 percent in June. The report is due at 8:30 a.m. ET.
At 7:16 a.m. ET, Dow e-minis were down 103 points, or 0.4 percent. S&P 500 e-minis were down 12.75 points, or 0.45 percent and Nasdaq 100 e-minis were down 40.25 points, or 0.54 percent.
A surge in high-flying stocks such as Apple and Amazon, as well as strong earnings have driven U.S. stocks near record levels, suggesting that investors have largely shrugged off trade worries.
Intel dropped 2.4 percent in premarket trading after Goldman Sachs downgraded the stock. Micron also fell 1.8 percent.
Dropbox fell 6.2 percent despite a better-than-expected quarterly report.
Tesla's shares rose 0.7 percent. Reuters reported the electric car maker's board is seeking more information about how Elon Musk plans to take the company private. (Reporting by Amy Caren Daniel in Bengaluru; Editing by Anil D'Silva)