Xref: utzoo comp.sys.dec:530 comp.arch:3484
Path: utzoo!mnetor!uunet!husc6!linus!philabs!pwa-b!anneser
From: anneser@pwa-b.UUCP (Dean Anneser)
Newsgroups: comp.sys.dec,comp.arch
Subject: 8036 counter/timer chip
Message-ID: <157@pwa-b.UUCP>
Date: 17 Feb 88 17:56:31 GMT
Organization: Pratt & Whitney Aircraft, E. Hartford, CT
Lines: 35
Keywords: DEC, KXJ11-CA, KXT11-CA, frequency data

Help !  Has anyone out in netland had experience with the 8036 counter/timer
chip that is used on DEC's KXJ11-CA/KXT11-CA single board computer.  I have
a problem that I cannot resolve.  I've talked with the KXJ11 product group
at DEC, AMD (Advanced Micro Devices), and ZILOG, to as of yet, no avail.

The task I'm attempting is to measure the inter-pulse interval of a 
signal from 10 Hz to 5000 Hz, using the 16 bit counter_timer_2, linked with
the 16 bit counter_timer_1, to create a 32 bit counter_timer (counter_timer_2
is the most significant word, and counter_timer_1 is the least significant). 
The clock is a 2MHz clock.  

At higher, frequencies, the inter-pulse interval at a 2MHz time base can
be represented in one 16 bit word (counter_timer_1).  At lower frequencies,
the count value reguires more than 16 bits to be represented.  The problem
I'm seeing, is that counter_timer_2 is not decremented with the FIRST
transition through zero, of counter_timer_1.  As the input signal's frequency
decreases, and counter_timer_1 makes an additional transition through zero,
counter_timer_2, then will decrement (what appears to be) correctly, but its
value is one greater than it should be.

Is there anyone out there at ZILOG, DEC, SGS, AMD, SHARP, or anywhere else,
who could be of assistance.

Thanks in advance.

Dean W. Anneser
Pratt & Whitney Aircraft
East Hartford, CT  06108
{philabs,utah-gr}!pwa-b!anneser

-- 
Dean W. Anneser
Pratt & Whitney Aircraft
East Hartford, CT  06108
{philabs,utah-gr}!pwa-b!anneser