User`s guide

Hardware Interrupts

4-12

You need to enter only the name of the ISR that is called in response to a

hardware interrupt in the Property Page of the corresponding HWI object in

the Configuration Tool. DSP/BIOS takes care of setting up the interrupt table

so that each hardware interrupt is handled by the appropriate ISR. The

Configuration Tool also allows you to select the memory segment where the

interrupt table is located.

The online help in the Configuration Tool describes HWI objects and their

parameters. See HWI Module in the TMS320 DSP/BIOS API Reference

Guide for your platform for reference information on the HWI module API

calls.

4.2.2 Disabling and Enabling Hardware Interrupts

Within a software interrupt or task, you can temporarily disable hardware

interrupts during a critical section of processing. The HWI_disable and

HWI_enable/HWI_restore functions are used in pairs to disable and enable

interrupts.

When you call HWI_disable, interrupts are globally disabled in your

application. On the C6000 platform, HWI_disable clears the GIE bit in the

control status register (CSR). On the C5000 and C2800 platforms,

HWI_disable sets the INTM bit in the ST1 register. On both platforms, this

prevents the CPU from taking any maskable hardware interrupt. Hardware

interrupts, therefore, operate on a global basis, affecting all interrupts, as

opposed to affecting individual bits in the interrupt enable register. To

reenable interrupts, call HWI_enable or HWI_restore. HWI_enable always

enables the GIE bit on the C6000 platform or clears the INTM bit in the ST1

value to the state that existed before HWI_disable was called.

4.2.3 Impact of Real-Time Mode Emulation on DSP/BIOS

TI Emulation supports two debug execution control modes:

❏ Stop mode

❏ Real-time mode

Stop mode provides complete control of program execution, allowing for

disabling of all interrupts. Real-time mode allows time-critical interrupt service

routines to be performed while execution of other code is halted. Both

execution modes can suspend program execution at break events, such as

occurrences of software breakpoint instructions or specified program space

or data-space accesses.