Path: utzoo!censor!isgtec!bmw From: bmw@isgtec.uucp (Bruce M. Walker) Newsgroups: sci.electronics Subject: Re: micro-controller (answers to Z8 questions) Summary: PWM can be done Message-ID: <675@isgtec.UUCP> Date: 4 Oct 90 16:57:46 GMT References: <656@isgtec.UUCP> <1672@ole.UUCP> <8638@ncar.ucar.edu> Sender: news@isgtec.UUCP Reply-To: bmw@isgtec.UUCP (Bruce M. Walker) Distribution: sci.electronics Organization: ISG Technologies Inc. Mississauga Ont. Canada Lines: 25 In article <8638@ncar.ucar.edu> hpoppe@ncar.ucar.edu (Herb Poppe) writes: > If there is not an EEPROM or windowed EPROM version of these devices, what > device (or development system) is used to develop/test software. I assume that you would breadboard with one of the 40-pin piggyback EPROM versions and simply ignore the extra pins that it has (that aren't bonded-out on the 18-pin version) while developing. > Are the timer(s) in the 18-pin devices capable of measuring the widths of > a PWM input while simultaneously generating an independent PWM output? PWM input can be measured by setting one of the timers into "gated internal clock" mode. The timers aren't capable of generating PWM output "unassisted" but a simple scheme will do it. The Z8's interrupt response time is *very* fast; so, simply set the timer into modulo-n count mode, enable the timer interrupt, and write a new down-count value to the timer every time the interrupt is triggered. For example, if the desired PWM duty cycle is 40%, alternately program the down count to be 60, then 40, then 60 and so on. -- bmw@isgtec.uucp [ ..uunet!utai!lsuc!isgtec!bmw ] Bruce Walker