Discussion about the Korg PolySix synthesizer

Hi,

   Let's not mix reset with interrupt, OK?  

   RESETb on the 8048 is an active low signal that puts the CPU in 
a known condition, ready to start executing code once the signal
is released.   It is a low level to reset the CPU, and high to let it run.
Pretty much all CPU's need a reset signal to put them into a known 
state at power up (although some generate the signal internally).
If you don't have a storage scope, it will be hard to see that reset is
low when you power up.   Mainly you are just checking to see that it's
high normally, to let the CPU run.

   In general, RESETb would be asserted for a long enough time to 
let the crystal oscillator start up, and the 5V power stabilize.    The oscillator
would only take a few mS to get going, typically, but reset is often asserted
for maybe 100-200 mSec, since all that does is make the start-up take a little
longer and you want to make sure the CPU is reset properly.

    Bob

--------------------------------------------
On Sun, 2/7/16, jw_dewdney@yahoo.com [PolySix] <PolySix@yahoogroups.com> wrote:

 Subject: Re: [PolySix] Re: The Post I didn't want to make....
 To: PolySix@yahoogroups.com
 Date: Sunday, February 7, 2016, 1:31 PM
     
       
       thanks for the suggestions Bob! no... i used the
 22pf cap on the materials list... i came across the post
 about the 10pf replacement just yesterday in fact. the one
 thats supposed to be 10pf measured closer to 3pf... though
 its pretty hard to get an accurate fix on values in the low
 pf range even with really good equipment as you know. i
 think ill order some 10pf caps and do some replacing on the
 board.
 i asked if this
 was some kind of 'normal condition' because someone
 just below in a post who just did the same board swap just
 mentioned something cryptic about loading factory programs
 and how now 'more of the lights seem to be going
 away'... or something to that effect... perhaps i should
 ask him...!
 also... is
 there a FAQ somewhere here on relevant problems? or
 something from Jed on 'startup procedures' and
 troubleshooting? im having a bit of a hard time getting
 relevant search results in this group. as for the reset pin
 on the processor... what kind of input does in need to start
 the interrupt? short to ground? guess i should read the
 manual for that processor...
 i could also try swapping processors
 i guess (have two more p6s to do!... hope i can get one of
 em right!!). id have tried the board in one of the other p6s
 though it really looks as though the problem is coming from
 the new board...
 
     
      
 
     
     
 
 
 
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