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VxWorks

BSP Developer’s Guide, 6.0

106

Serial Drivers

The old style of serial drivers, those used before VxWorks 5.3, reside in the

target/src/drv/serial directory.

To manage information about a serial device, sysLib.c uses a device descriptor.

This device descriptor also encapsulates board-specific information. For example,

it typically includes the frequency of the clock and the addresses of the registers,

although the details are dictated by the device in question. In sysLib.c, the serial

device descriptor is declared outside the routine definitions as:

TY_CO_DEV tyCoDv [NUM_TTY]; /* structure for serial ports */

This array is initialized at run-time in sysHwInit( ). The TY_CO_DEV structure is

defined in the device header file (for example, target/h/drv/serial/z8530.h).

Timer

The generic timer drivers reside in the target/src/drv/timer directory. The

templateTimer.c template file is included in this directory. When writing a timer

driver, base the driver on this template file, then modify the BSP sysLib.c file to

include the driver as needed. If the BSP can only access a single timer, the BSP must

support the system clock and not the auxiliary clock. This means that

sysAuxClkConnect( ) must return

ERROR.

The following macros are used for parameter checking in VxWorks timer drivers,

and must be defined in each BSP’s bspname.h file:

SYS_CLK_RATE_MIN

Defines the minimum rate at which the system clock can run. Unless hardware

constraints dictate otherwise,

SYS_CLK_RATE_MIN must be less than or equal

to 60 Hz.

SYS_CLK_RATE_MAX

Defines the maximum rate at which the system clock can run. Unless hardware

constraints dictate otherwise,

SYS_CLK_RATE_MAX must be greater than or

equal to 60 Hz.

NOTE: These serial drivers are provided for backward compatibility with

VxWorks 5.2 and earlier. All current generation BSPs should use SIO drivers

instead.

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