Inside Macintosh: Open Transport /

Chapter 16 - Serial Endpoint Providers / Serial Endpoint Providers Reference

Serial-Specific Commands

I_SetSerialBreak

This command controls a break signal on the serial connection. It is a 4-byte unsigned integer. Its value is kOTSerialSetBreakOff to unconditionally turn the break signal off, kOTSerialSetBreakOn to unconditionally turn the break signal on, and any other value to turn the break signal on for a specified number of milliseconds. The following line of code turns the break on:

OTIoctl(theSerialEndpoint, I_SetSerialBreak, kOTSerialSetBreakOn);

Asserting a break signal is equivalent to using a serial driver control call with a csCode value of 12, and deasserting the break signal is equivalent to using a csCode value of 11.

Note

Note that, contrary to some readers' expectations, the on value is 0 and the off value is 1.