Easily Use Multiple Pin Multiplexing Files with VTOS
Pin multiplexing allows an embedded developer to choose how internal processor signals are configured at run time and mapped to external pins, providing the functionality they require. This technology allows for smaller and more cost effective processors, without reducing options. If one design requires PCI Express signals, they can create a pin configuration allowing the processor signals to be mapped to external PCI Express pins. If the next design requires Serial Rapid I/O, the same processor can be used with a new pin configuration supporting SRIO signals.
Pin multiplexing was patented in April 2007 by Infineon Technologies AG (US 7,199,607). Many modern day high-end processors use pin multiplexing to allow designers a myriad of functional options in the smallest package – processors such as the Intel’s Core i7, TI’s Sitara AM335x, Freescale’s i.MX6, and others.
These processors contain many peripheral interfaces. Embedded developers can use pin multiplexing to choose how the processor’s terminal pins will be routed to a particular signal choice. For example, one processor terminal may be multiplexed into eight different signals; the number of signal choices varies by processor.
As a way of reducing the effort to assign and validate the assignment of processor pins, processor manufacturers are providing pin multiplexing tools to graphically configure and validate pin routing choices. These tools can be used to generate source files that can be compiled into boot loaders and operating systems. The typical process is to generate a file, compile it in, and have the boot loader or operating system use that file during early hardware initialization. Because pin multiplexing is processor-dependent, it is not managed by Linux conventional drivers, and must be built in to every platform-dependent OS distribution.
A new feature of Kozio’s VTOS software is the ability to configure a running VTOS image with one or more pin multiplexing files. The process is to generate your pin mux file using the tool provided by the silicon manufacturer. Then use a VTOS Developer GUI to import that pin mux file. The VTOS Developer GUI will convert the file into a Kozio script file for run-time use. The user can then run that pin-mux file to have the VTOS firmware use those pin settings. This process provides a quick way to handle multiple pin configurations using VTOS. The same pin mux file can be used during test development, or on the manufacturing floor.
This new feature of VTOS provides a quick and easy way to handle multiple pin multiplexing configurations, a common step when dealing with today’s high-end processors.