HSER and Servo

[Marcwolf]

In another post Goeytex said

Don't give up !

It then send its data to another Picaxe that uses background serial receive that should not affect the servo command.

Can Technical confirm this - Background (Hser) serial commands do not affect the Servo?

There has been a number of instances where I have needed to use Serial communications and have servo(s) running at the same time, especially when using the PicAxe as a servo controller


It would be great if this works.. Otherwise can I add Servo and Serial do not interfere with each other to the Wish List

Dave

 

[Goeytex]

I am working on this now with a 20X2. When I used one pin ( forgot which one) for servo, the hsersetup command seems to have killed the servo output. Yet with output B.2 it seems to work ok. This is only preliminary and need to be investigated further. I am gonna do thorough testing and will report results.

 

[Technical]

It depends which chip you are using.

M2's have a very simple hserin system, where two bytes are received in the background and just stored until necessary. This has no effect at all on servo, but data can only be sent with gaps betwee the bytes (so the user PICAXE program can retrieve and process the data before the next bytes are sent).

X2's have a more complex system, where the PICAXE firmware 'notices' that a byte has been received and transfers it to scratchpad. This allows much more data to be sent back-to-back. However 'the moving the data out to scratchpad' takes a very small amount of time, which may marginally affect servo performance.

 

[Marcwolf]

Many Thanks Technical.

This would be fine for my needs with the M2's as I can make a very simple 2 byte control language.

It's more a case where the M2 will be running one of several set sequences and I will need to tell it to change the sequence. If I wasmonitoring the serial as well then that would interfere with the Servo system.

Take Care
Dave