MDK-ARM Keil, MDK-ARM Datasheet - Page 18

• Manufacturer Part Number: MDK-ARM
• Description: KIT REALVIEW MCU DEVELOPMENT
• Manufacturer: Keil
• Type: Compiler and IDEr

Specifications of MDK-ARM

• For Use With/related Products: ARM MCUs
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18
We must let the µVision IDE utility
know that we are using RTX so that it
can link in the correct library. This is
done by selecting “RTX Kernel” in the
Options for Target menu, obtained by
right clicking on “RTOS”.
The RTX Kernel library is added to the
project by selecting the operating
system in the dialog Options for Target.
When using RTX with an ARM7 or ARM9 based microcontroller, calls to the
RTOS are made by Software Interrupt instructions (SWI). In the default startup
code, the SWI interrupt vector jumps to a tight loop, which traps SWI calls. To
configure the startup code to work with RTX we must modify the SWI vector
code to call RTX.
A part of RTX runs in the privileged supervisor mode and is called with software
interrupts (SWI). We must therefore disable the SWI trap in the startup code.
With Cortex-based microcontroller, the interrupt structure is different and does
not require you to change the startup code, so you can ignore this step.
You must disable the default SWI handler and import the SWI_Handler used by
the RTOS, when used with ARM7 or ARM9.
Undef_Handler
;SWI_Handler
PAbt_Handler
DAbt_Handler
IRQ_Handler
FIQ_Handler
In the vector table, the default SWI_Handler must be commented out and the
SWI_Handler label must be declared as an import. Now, when RTX generates a
software interrupt instruction, the program will jump to the SWI_Handler in the
RTX library. These few steps are all that are required to configure a project to
use RTX.
Exercise: First Project
The first RTOS exercise guides you through setting up and debugging an RTX-
based project.
IMPORT
B
B
B
B
B
B
SWI_Handler
Undef_Handler
SWI_Handler
PAbt_Handler
DAbt_Handler
IRQ_Handler
FIQ_Handler
Chapter 2. Developing With an RTOS
; Part of RTL