raspberry pi 3 model b+ support realtime
- andypugh
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						12 Aug 2019 20:11				#141996
		by andypugh
	
	
		
			
				
Interesting. You wouldn't normally expect that to work as the Pi3 ethernet is on the USB bus and that tends to make accurate timing impossible.
Pi4 has he ethernet on the PCIe bus, and then the servo thread at 1mS works fine with an ethernet board.
					
	
	
			 		
													
	
				Replied by andypugh on topic raspberry pi 3 model b+ support realtime			
			Hi everyone!
I just want to leave my experience here because I've been able to successfully use an Pi3b+ with a Mesa 7i92 + 7i77 + 7i84.
Interesting. You wouldn't normally expect that to work as the Pi3 ethernet is on the USB bus and that tends to make accurate timing impossible.
Pi4 has he ethernet on the PCIe bus, and then the servo thread at 1mS works fine with an ethernet board.
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						17 Aug 2019 12:08				#142386
		by spma
	
	
		
			
				
The next project I'll get a chance I'll invest some time testing it with the Pi4.
Simão A.
					
	
			
			 		
													
	
				Replied by spma on topic raspberry pi 3 model b+ support realtime			
			True but I tested it thoroughly and the 2.5ms of servo_thread period was more than enough for a 30yo SLOW lathe with a maximum joint precision of 0.05mm... and it outputted that precision while machiningInteresting. You wouldn't normally expect that to work as the Pi3 ethernet is on the USB bus and that tends to make accurate timing impossible.
Yes, the Pi4 would now be a better choice, but we're talking about a project I started almost 2 years ago...Pi4 has he ethernet on the PCIe bus, and then the servo thread at 1mS works fine with an ethernet board.
The next project I'll get a chance I'll invest some time testing it with the Pi4.
Simão A.
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