At 08:43 PM 7/29/97 -0400, you wrote:
>>
>> Hi,
>>
>> I am doing a project on Microchip's 17c42a microcontroller.=A0 I will be
>> needing a scaled down RTOS which can schedule different tasks.=A0 The RTOS
>> will be interrupted by various hardware interrupts and timers.=A0 I am=
>>  having
>> difficulty in implementing/designing the task scheduling and also task
>> preemption.
>>
>We've just finished having this discussion a couple of weeks ago. Frankly
>it cannot be done easily. This is due to the fact that the system stack
>isn't mapped into a user accessible address space. So the typical mechanism,
>stack swapping, isn't available.
>Hope this helps,
>
>BAJ

yes, you can't implement preemptive scheduling.. maybe round robin
only(non-preempt)
take a look at tics magazine (www.concentric.net/~tics/), online magazine
about RTOS.

I've changed my thesis from 17c44 to HC11 due to the 'HARDWARE STACK' on pic
I'm using labrosse's UCOS11.
BTW, for commercial product OR thesis?
good luck.

f