5 ms·
Yes, but even with rt-linux, you've got a jitter of potentially several dozen microseconds, and each interrupt routine will vary. With an AVR, your delay is 4 c
by Sanddancer 10y ago
Yes, but even with rt-linux, you've got a jitter of potentially several dozen microseconds, and each interrupt routine will vary. With an AVR, your delay is 4 clock cycles every time, which comes out to .2 microseconds at 20 Mhz. This is the kind of guarantee you can get with being on an intimate level with the chip which you can't get with any OS.
- deleted 10y ago[deleted]
- eru 10y agoAt least not any OS that's not geared for realtime from the ground up.
- tremon 10y agoIt's not just about the OS, it's about the platform (hardware). Even with a fully-optimized RTOS on a standard PC platform, you might run into millisecond-latency due to non-maskable interrupts, cache misses or bus contention (DMA bus-mastering kills any real-time guarantees). That's not even considering the stalls introduced by SMM or TPM instructions.
- jevinskie 10y agoI would think it would be difficult to achieve the low jitter of a simple, fixed # of cycles / instruction, architecture like AVR in a superscalar, cached, speculative architecture like modern X86 CPUs. A hard RTOS is necessary, but perhaps not sufficient with most X86 microarchs. Maybe you can disable some of that dynamic behavior via MSRs but probably not all.