IPC@CHIP Documentation - SC12 @CHIP-RTOS V1.10

Semaphore Protection
Interrupt Masking
RTOS Task Switch Lock
Critical Section Protection Methods Summary
CONTROL AND COMMUNICATION BETWEEN TASKS
IPC@CHIP Documentation Index
Multitasking Introduction
The @Chip-RTOS provides for a multitasking operation. A task provides a thread of execution. Each task has its
own context, including an instruction pointer and program stack. Each task in the @Chip-RTOS has a unique
priority of execution, providing a preemptive form of multitasking. By executing multiple tasks at the same time,
various activities can be performed concurrently.
Abbreviations Used
Acronym Stands For
API Application Programmers Interface
ISR Interrupt Service Routine
RTI Real-Time Interrupt
RTOS Real-Time Operating System
TCP/IP Transport Control Protocol / Internet Protocol
Table 1 ) Abbreviations
Reasons for using Multitasking
Here are some situations where multitasking can be helpful.
Different Priority Work
Probably the most compelling reason for using multitasking is when required activities have different
priorities. For example, an application with a user interface may need to be responsive to keyboard
entry from a user console while at the same time the program is conducting a time consuming
calculation or data base search. A low priority task could perform the calculation/data base search
while a high priority task periodically polls (or sleeps waiting) for keyboard input. Typically there would
be some communication between these two tasks, such as having the keyboard task cancel the
Page 220 / 400