Nov. 30--The financial crisis hammering Detroit's auto industry is sending shock waves to Silicon Valley, where a number of companies make the computer chips that have become increasingly vital components in cars and other vehicles.

And if Ford Motor, Chrysler and General Motors go belly up, as some experts fear, the repercussions in the valley could intensify.

"As soon as the automotive industry coughs, a lot of other companies get a cold," said Thilo Koslowski, who tracks that business for research firm Gartner. "That includes companies in the semiconductor industry and that includes a lot in the Bay Area. "... It's a relatively big market for them in Silicon Valley."

South Bay companies that supply semiconductors for carmakers include Intel, Atmel, National Semiconductor, Spansion, Altera, Maxim Integrated Products, Xilinx, Linear Technology and Cypress Semiconductor.

Even if the Big Three continue operating, but one or more of them files for bankruptcy protection from creditors, some chip makers might have trouble collecting what they are owed for the devices they sold the automakers, said Paul Hansen, who publishes the Hansen Report on Automotive Electronics.

"If you ship something to a company that goes bankrupt, you might get paid some huge discount and you might not get paid at all," he said.

At Atmel, which several experts called the biggest local supplier of chips for cars and trucks, the company's sales grew during the first

three quarters of this year, but have slowed in the fourth quarter, according to Matthias Kaestner, an Atmel marketing executive who declined to be more specific. Nonetheless, he noted that the company is somewhat shielded from the Big Three's woes because it sells many of its chips to European carmakers, which do not appear to be in as dire shape.

"Atmel's exposure to the U.S. auto industry is relatively small, hence the concerns are small," he said.

Computer chips control everything from the engine, transmission, brakes and cruise control to dashboard instruments, air conditioning, security alarms and malfunction warning sensors.

The brainy devices even enable carmakers to offer collision-avoidance systems such as the one Volvo introduced in January, which automatically brakes the vehicle when it senses an imminent rear-end crash and alerts the driver if the car veers from its lane without a turn signal being flashed.

Although experts say most chips used in cars come from companies elsewhere -- notably Freescale Semiconductor of Texas -- precise data on how much Silicon Valley chip companies contribute to that market is difficult to obtain.