Real-time clock

[Eric Christopherson]

I can see that my uIEC-SD has an RTC on it, via directories with
timestamps ($=T) and the T-R/T-W commands. But it doesn't keep time once
the device is powered off.

I see at <http://www.go4retro.com/2011/08/23/uiecsd-3-2-vs-uiecsd-3-1/>
that "Although not populated on the PCB, there are pads for a Dallas
DS1307 (or compatible) RTC with battery backup". Is this a little
inaccurate -- my device has an RTC but no battery? Or is it possibly the
case that I have a battery but it's bad?

--
Eric Christopherson

[RETRO Innovations]

The pads are there on the 3.2 version, but it is not populated.

Jim


--
RETRO Innovations, Contemporary Gear for Classic Systems
www.go4retro.com
store.go4retro.com

[Eric Christopherson]

On Sun, Jun 21, 2015, RETRO Innovations wrote:
> On 6/21/2015 7:41 PM, Eric Christopherson wrote:
> >I can see that my uIEC-SD has an RTC on it, via directories with
> >timestamps ($=T) and the T-R/T-W commands. But it doesn't keep time once
> >the device is powered off.
> >
> >I see at <http://www.go4retro.com/2011/08/23/uiecsd-3-2-vs-uiecsd-3-1/>
> >that "Although not populated on the PCB, there are pads for a Dallas
> >DS1307 (or compatible) RTC with battery backup". Is this a little
> >inaccurate -- my device has an RTC but no battery? Or is it possibly the
> >case that I have a battery but it's bad?
> >
> The pads are there on the 3.2 version, but it is not populated.

Right, but when you say "the pads" you're just referring to the pad for
a battery, correct? Or, if there is neither RTC nor battery, is it
possible for the device to tell time anyway?

--
Eric Christopherson

[RETRO Innovations]

On 6/21/2015 10:08 PM, Eric Christopherson wrote:
> Right, but when you say "the pads" you're just referring to the pad for
> a battery, correct? Or, if there is neither RTC nor battery, is it
> possible for the device to tell time anyway?

The pads for the battery, the crystal, and the RTC IC.

Jim

[Eric Christopherson]

On Sun, Jun 21, 2015, RETRO Innovations wrote:

OK. How is it telling time now? Does it just count clock cycles like the
CBM TOD?

--
Eric Christopherson

[RETRO Innovations]

While the unit is operating, it is indeed counting clock cycles. It is
very accurate, but it's not a RTC.

[mistermsk]

Just curious if there is a limit. If I leave my C64 on for a year for instance, is it going to have an issue? Is there a Max count and/or does it reset besides power cycling?

[RETRO Innovations]

On 6/22/2015 11:58 AM, mistermsk wrote:
> Just curious if there is a limit. If I leave my C64 on for a year for
> instance, is it going to have an issue? Is there a Max count and/or
> does it reset besides power cycling?

:-)

sd2iec uses the 32 bit mktime() function from Linux (v2.6.20, to be
exact). It will overflow sometime in 2038.

[David L. Haynes]

Interesting read.

https://en.wikipedia.org/wiki/Year_2038_problem

David

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[Terry Raymond]

What is the overflow?

-Terry Raymond

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[Dave McMurtrie]

If you read the wikipedia page that David Haynes linked to, it's explained in there.  The mktime() function that Jim mentioned returns a time_t value to the caller.  time_t is implemented as a signed, 32 bit integer that represents the number of seconds which have elapsed since Unix epoch (January 1, 1970 00:00:00 UTC).  2147483647 is the largest value that can be stored in a signed 32 bit integer, so when 2147483648 seconds have elapsed since the start of Unix time, that time_t value will overflow to a negative value and Unix will think it's 1901.  I will likely be retired or dead before this matters to me in my job.  Hopefully the former.

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[Terry Raymond]

Yep me too :)

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[Eric Christopherson]

Does anyone out there have a how-to or advice on attaching the
required parts for the RTC? Disclaimer: I have shaky hands under the
best of circumstances, and have only soldered once (on my Palm T|X). I
was a nervous wreck doing it, but then I thought it had actually
worked... unfortunately the handheld was really unstable from then on
:(

Also, I'm wondering if anyone has any guide to putting a uIEC-SD in a
case (e.g. Hammond 1551RBK, as recommended by Jim).

[Terry Raymond]

Hi Eric,

Jim Peters puts uiec SD boards into cartridge cases.

tj...@mchsi.com
Hope that may help.

-Terry Raymond

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[Jim Peters]

I have mounted the uIEC-SD in Cartridge cases and in QuadportIEC cases.
I have cases ready to mount or can send you pictures of the cartridge
case mounting or instruction sheets (PDF) on mounting the uIEC-SD in one
of Jim Brains QuadPortIEC units.
Jim Peters
tj...@mchsi.com