Simonk ESC & PWM

Ruby · Joined: 04 Jul 2014 Posts: 44

Hi everybody. I need help with pwm. I am using 16f877a. If I am not wrong I need 50hz for esc.

Ttelmah · Joined: 11 Mar 2010 Posts: 19520

Look in the code library for _servo_ code.

ESC's use the same data format as servos (they are driven by radio controls commonly).

Ruby · Joined: 04 Jul 2014 Posts: 44

Thanks for reply. What you mean with look in library?

Ttelmah · Joined: 11 Mar 2010 Posts: 19520

Haven't you actually _looked_ at the layout of this forum?.

It has three sections:
'General CCS Discussion'
'Code Library'
'CCS ICD/Mach X/Load-n-go'

The 'code library' contains hundred (thousands?), of sections of code to help. There are at least three examples there, of code to drive various numbers of servos.

Ruby · Joined: 04 Jul 2014 Posts: 44

Ok but if I can't find there what I am looking for how can I move the post?

temtronic · Posted: Fri Nov 14, 2014 12:09 pm

near top of this screen is a button called 'search',click on it and use RS servo or ESC servo', selct 'and' wait a bit...you'll get 300+ hits. It's up to you to scan,read,select which has the code that is applicable.
Presumably ESC means Electronic Speed Control... and yes, refresh rate will be 50Hz UNLESS it's the newer 'digital' RC servos.

hth
jay

Ruby · Joined: 04 Jul 2014 Posts: 44

I bought this
http://m.ebay.com/itm/161432910116

asmboy · Joined: 20 Nov 2007 Posts: 2128 Location: albany ny

Have you started to write the code you need?

Ttelmah · Joined: 11 Mar 2010 Posts: 19520

These will accept the 400Hz digital servo signals, (as well as the old 50Hz standard).

Ruby · Joined: 04 Jul 2014 Posts: 44

How do you know? I couldn't find any datasheet of them? 400 better right?

Ttelmah · Joined: 11 Mar 2010 Posts: 19520

The 'Simonk' in the description, is the firmware in the ESC's. He wrote an improved version to give faster refresh for things like multi-copters, where being able to change the speed more quickly helped give the fine control required.
It'll still accept the slower refresh, if needed.
Whether it is 'better', depends on what you are doing. For things that need very rapidly adjusted speeds, yes, better. However it means that the code feeding it must be very careful to not give incorrect values, since these result in high current spikes, and rough output.

Realistically, you'd get much better response, by switching to one of the more modern PIC's with hardware PWM's that can go to this sort of frequency (some of the motor control ones). Simpler, and easier to update the speeds accurately.