Coma FW-C2800 User's Guide download pdf (Page 172)

Timers, Interrupts, and the System Clock

Thread Scheduling 4-67

4.8 Timers, Interrupts, and the System Clock

DSPs typically have one or more on-device timers which generate a

hardware interrupt at periodic intervals. DSP/BIOS normally uses one of the

available on-device timers as the source for its own system clock. Using the

on-device timer hardware present on most TMS320 DSPs, the CLK module

supports time resolutions close to the single instruction cycle.

You define the system clock parameters in the DSP/BIOS configuration

settings. In addition to the DSP/BIOS system clock, you can set up additional

clock objects for invoking functions each time a timer interrupt occurs.

On the C6000 platform, you can also define parameters for the CLK module’s

HWI object, since that object is pre-configured to use the HWI dispatcher.

This allows you to manipulate the interrupt mask and cache control mask

properties of the CLK ISR.

DSP/BIOS provides two separate timing methods—the high- and low-

resolution times and the system clock. In the default configuration, the low-

resolution time and the system clock are the same. However, your program

can drive the system clock using some other event, such as the availability of

data. You can disable or enable the CLK Manager’s use of the on-device

timer to drive high- and low-resolution times. You can drive the system clock

using the low-resolution time, some other event, or not at all. The interactions

between these two timing methods are shown in Example 4-18.

Figure 4-18. Interactions Between Two Timing Methods

Default configuration:

Low-resolution time and

system clock are the same

Low-resolution time

and system clock

are different

Only low- and high-

resolution times available;

timeouts don't elapse

Only system clock

available; CLK functions

don't run

No timing method;

CLK functions don't run;

timeouts don't elapse

Not possible

CLK module drives

system clock

CLK manager

enabled

CLK manager

disabled

Other event drives

system clock

No event drives

system clock

1 2 ... 167 168 169 170 171 172 173 174 175 176 177 ... 275 276

Comments to this Manuals

No comments

Coma FW-C2800 User's Guide Page 172

Comments to this Manuals

Related products and manuals for Telephones Coma FW-C2800