In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Peter Van der Zee wrote:

Hi cbmeeks;

It's a little tricky, and quite hard to explain, but I have been able to keep around 65 (thats all I needed; there is no practical limit) SX's running continuously in sync for almost ten years now. Each uses its own (50 MHz) resonator, and each will lock onto the selected "master" to one instruction; 20 nSec. If lock is lost on one, say a power down on it, it will regain a lock typically in 100 uSec.

In order to achive these results you need to be VERY precise in how you write your software in the ISR routine, Although in concept it's very simple, it's not suitable for the "casual" programmer, and tools such as a GOOD oscilloscope is pretty much a neccessity. And yet, once the syncing method is established, almost any other application software can be merged in with it, including my 8 thread pre-emptive realtime operating system. I principally use it with Virtual Peripherals such as ADCs, DACs, UARTs, digital inputs, relay outputs, etc. for industrial monitoring and control.

Cheers,

Peter (pjv)

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