Re: C64 reset timing

From: silverdr_at_wfmh.org.pl
Date: Mon, 25 Jan 2021 21:06:55 +0100
Message-Id: <369D4EB3-BFCC-4DFF-8BB1-C2385B7182EB_at_wfmh.org.pl>
> On 2021-01-25, at 20:58, groepaz_at_gmx.net wrote:
> 
> Am Montag, 25. Januar 2021, 20:46:42 CET schrieb silverdr_at_wfmh.org.pl:
>> When testing BeamRacer prototypes on as many different C64 / SX64 boards as
>> possible I remember encountering a problem with one machine, which we had
>> to take into account and work around. The root issue with that particular
>> board was that upon power-up the _RST (reset) line was not asserted for
>> some prolonged time but became inactive (almost?) immediately once VCC
>> stabilised. This didn't seem to affect the way the machine worked and I
>> probably wouldn't notice it at all if it wasn't causing issues with our
>> add-on. While now I am yet to find that particular machine back and analyse
>> it thoroughly, I am wondering that's something, which could be described as
>> a common failure or feature? Has any of you in the know encountered
>> anything similar?
> 
> sounds like a broken capacitor in the reset circuit :)

It does sound like a hardware failure. I have to find that particular board back and check it thoroughly out. In the meantime I am interested in how common that might be. With the BR it was not critical - just unexpected. In the next project though, it would be hard to live with this. Obviously I don't feel like accounting for failed hardware but if that's something typical then I'd have to rethink.

-- 
SD! 
Received on 2021-01-25 22:00:21

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