Falcon030 RTC with external battery

[Arne]

I had this on my to-do list for quite some time as I am out of DS12887 replacements.

So I designed a PCB with a compatible DS12885 that needs an external quartz and a 3V source. I decided for a CR2032, but on the bottom side of the PCB will be a connector of the same type as in MegaSTE/TTs for connecting an external battery-pack.
On the left edge of the PCB you see a CMOS-Clear Jumper which isn't available on DS12887. Short circuit it for a moment and the Falcon will get Alzheimer's disease immediately losing all settings except date/time.

As I will manufacture a small batch: is there any interest here? Price will be 23,-EUR for a PCB with all components, 24pin socket for the mainboard and a new CR2032.

cheers, Arne

[Guest]

rechargeable ??
handy feature you need only make sure the cell cant leek out to the chassis
i thought of a solar cell on the top case feeding +3-5v to keep the internal cell fresh,,,

[Arne]

No, not rechargable.
I was thinking about this and had a look:
http://www.pollin.de/shop/dt/ODQ5ODI3OT ... 0_1VC.html
Only 7mAh. CR2032 has ~200mAh. My Falcons often reside on the shelf for months without use.

[qq1975b]

Very interesting. You avoid to use the internal battery of the DS12885 and use directly the external one, right? The DS is socketed too and all fits under the metal case, doesn't it?

I am interested

[simonsunnyboy]

I'm interested - and count me in for a visit at your place for mounting it into my F030

[Arne]

Very interesting. You avoid to use the internal battery of the DS12885

Nope. Get a DS12885 datasheet and you will see that it has no internal battery.
Neither a 32.768Hz quartz. That's why its the size of a 6850 ACIA.

The DS is socketed too and all fits under the metal case, doesn't it?

Exactly. I prefer using sockets. And it fits beneath the metal shielding. That's why I had to move the DS position far to the back.

I'm interested - and count me in for a visit at your place for mounting it into my F030

Anytime when the final PCBs are ready to be mounted.

[Kermit7204]

I want one too!!

[jok]

Definitely interested in two!

[Arne]

For those who are interested in this hardware: please monitor this thread.
I will check the settings of my Falcon next weekend again to see if it loses them.
Just found out that using the test-cartridge will definitely destroy the setup. Needed to set them again

[Dal]

Nice. I'm down for 2 of these when they are available.

[Arne]

PCBs arrived.



Checked them with the F030 Testkit:



Can set time/date with XControl or ZControl and NVRAM settings with BootConf by Uwe Seimet.

If you are interested in such an add-on send me an email to order-rtc [at] team-yankee [dot] net.
Price for one kit is 23.50€ + postage and you will get the fully assembled kit with DS12885, a new CR2032 battery and a 24pin socket for the F030 motherboard:


Cheerio, Arne

[Dal]

Fab - email sent!

[Arne]

Sold out.

[Dal]

Oh dear - I sent an email but didn't see your order form come back. I've just filled it in and returned it - hope my order was counted...

[mdivancic]

Wow, you should be able to sell more of these...

[Arne]

As some time passed now:
anybody already dared to mount that PCB or do they sit on your shelf?

If there is at least interest for another 15 kits here then I will order new PCBs and parts next year.
Price would be 23,-€ for the populated PCB (including DS12885) and a socket for the mainboard but no
CR2032 as I saw that it is against DHL rules to send batteries via airmail.

[Knezzen]

Im interested in two as well!

[Dal]

As some time passed now:
anybody already dared to mount that PCB or do they sit on your shelf?

If there is at least interest for another 15 kits here then I will order new PCBs and parts next year.
Price would be 23,-€ for the populated PCB (including DS12885) and a socket for the mainboard but no
CR2032 as I saw that it is against DHL rules to send batteries via airmail.

Yes I have it installed in my main machine - it has been absolutely perfect. In fact, I completely forgot it was there until I saw this thread pop up again!

[Arne]

Seems this doesn't generate much interest, so I will not go for a second batch.

[qq1975b]

I have installed it too. Works perfect

[Atari030]

Any left, Arne? The second falcon is near due and I've had enough of removing clocks.

[qq1975b]

Don't you socket them?

[Atari030]

I did on my tower case, but my stock machine is coming up to its due date. You can use a socket with this adapter and I am a big fan of backward compatibility. Mind you, my towered Falcon has no CPU or GAL's.

[Guest]

i use a solar cell to recharge the nvram battery via a diode 1n4148
i use a 3.6v lithium cell {same one as the stbook MN something ..}
and a diode to charge it from a 5v panel from one of the garden lights you get free with fuel.. ... or for like 2 quid
they even have a holder and usually two 1.5v lithium cells AA or AAA {physical size of them tells you what cells they use}
they are poo at there job but harvestable for bits cheep and most people have them in a garden if you have one...
free and cheep and reliable ... you can even resuse its charging circuit if you like
but two diodes is plenty...

they are just not reliable in a garden enviroment as they just rot and get broken from the mower etc
and people dont turn them off and let the cells charge up
so they die ...
you gota feel sorry for the old garden light and give its cells a new home with a purpose
so you dont even need to buy a battery... two 1.5v cells is magic will last 100 years on there own... without a charge
the original charging circuit and supply to the led will yield 3v all the time

another 1n4148 feeds the nvram if you use a 3.6v cell with the now 3v due to the drop accross the diode
im gona mod the TT the same way,...
dont worry the solar cell is 5v this gives some overhead for low light
in direct burning sunlight it can only provide like 200ma
enough to charge but not damage... the cells it will provide 20ma in any light .. so plenty to supply the nvram and the battery
from getting exhausted...
reusing the old charging circuit is prob a good idea as long as you have a steady 3v supply to the nvram
there is no issues

i also added a nvram memory block reset button ... to my falcon and TT

think the pcb is a good idea but so is a burr drill and a battery
replacing the nvram with a better one is a good idea...
i think adding this adds another interface to work with

with the TT i found very little info on what details it stores much like the falcon
and it can become corrupted and the machine can fail too boot
a reset of the nvram and power up again fixes it...
sometimes,.... same as the falcon
not all NVRAM ics work reliably the 88+ version doesnt ....
its a raw circuit but works for me

the nvram battery im my acorn pc700 i will also add a solar cell too it uses a different setup and a more hungry chip
its a bit bigger and needs more current so two cells in parallel with isolator diodes
will provide enought current to keep it topped up

i cant use this board as i have bonded heatsinks on all ics ...
so a burr and battery is my only solution past just changing the ic

you can add a 3.2v clamp zener diode if you like at the nvram
to make sure the volts dont go too high on a bright day...

[Hardcore8UK]

Hi Arne,

Do you still have one of these?, is there much soldering to fit it, have stock Falcon 14mb,

Thank.