RTC on the a1200 MB ?

11 March 2012, 13:45

What would be needed to put an RTC like RF5C01A on the a1200 motherboard ? I guess an oscillator and some additional components. And would it work at all ?

I have a spare MB that I just woke up from a mem failure by soldering in some new chip ram circuits and it seems to work fine. But got curious on the space for the RTC next to the ram's and if it is not to much tinkering.....why not..try

Jope · 11 March 2012, 16:55

Check out the A1200 schematics. They have the optional clock circuit drawn into them.

fordav1 · 23 July 2017, 12:14

I realize this is an old thread, but I am not able to find the answer... did anyone actually add the parts onto the A1200 motherboard for the RTC (as per the schematic) and get it working? It's only a couple of dollars in parts and 30 minutes with a soldering iron. I have tons of spare parts here to do it, all I would need to buy is the RTC chip. SMD is no problem for me so I can do the work, but I'm curious if anyone has done it and if it worked?

RedskullDC · 23 July 2017, 14:56

Hi Fordav1,

Quote:

Originally Posted by fordav1

...I'm curious if anyone has done it and if it worked?

Yes, it does work.

Did it to a 1D4 A1200 many years ago, though I no longer have it.

I acquired it with an early GVP A1230 Turbo+ card installed, which doesn't have an RTC.

Putting the components on the motherboard seemed liked the best option at the time to leave the "clock" port free for a silver surfer board.

Cheers,
Red

fordav1 · 23 July 2017, 15:15

excellent, thanks for the info. I'll give it a try.

c4u2sky · 24 July 2017, 02:48

thanks. I will try it right after reading this article

fordav1 · 05 August 2017, 16:55

Just a quick update: I've added the parts (minus RTC) and the battery charges as normal. Still waiting for the RF5C01A chips to arrive. I had a hell of a time sourcing them, they are seriously not easy to find now in the SOIC18 package. I ended up going with some random seller on aliexpress who didn't speak English very well.

ondrej · 28 October 2021, 14:32

Quote:

Originally Posted by fordav1

Just a quick update: I've added the parts (minus RTC) and the battery charges as normal. Still waiting for the RF5C01A chips to arrive. I had a hell of a time sourcing them, they are seriously not easy to find now in the SOIC18 package. I ended up going with some random seller on aliexpress who didn't speak English very well.

Sorry for reviving this old topic. Did you manage to get this to work? I'm thinking of doing the same.

Charles voner · 29 April 2023, 22:33

Hi,
I'm reviving this old topic too because somehow my RTC circuit has stopped working and I'm wondering if just adding this chip will it restore my RTC ability. Whatever I do the RTC is not found anymore. I just added a battery to my 1260 and it kept time for 2 weeks then just stopped because it cannot find any clock anymore. Would this chip restore my clock or is something else preventing it from working? The +5v is present on the clockport. Clockport module does not work either although these work on my other Amiga 1200. Thanks.

Mick · 10 May 2023, 09:53

I was going to say that I don't think it's possible since according to the RF5C01A datasheet it is an 18pin part, whereas the A1200 footprint is 20pin and the pins will be messed up. My assumption was that Commodore messed up the circuit/schematics and never bothered to fix it but people claim to have done the mod successfully so maybe Ricoh made it in 20pin too?

Daedalus · 10 May 2023, 10:48

Regarding the Blizzard 1260's RTC, are you using the correct battery? Some Blizzards were fitted with VL2032s, others with CR2032s, and they're not compatible. Fitting the incorrect type will produce symptoms you describe: the clock working for just a short time. Another issue I've had on one B1260 that was fitted with a CR2032 was the failure of a protection diode on the board, which gave similar symptoms.

Motherboard clockport modules will be hit and miss when the accelerator has its own RTC built in. Some will ignore it, some will defer to it, some will produce garbage due to contention when both RTCs are read at the same time.

george7272 · 29 August 2023, 17:44

I have an ACA1234 with an rtc module and I was thinking to put one rtc on the motherboard.
Do you know if the ACA ignores the rtc from the motherboard when the ACA is active?
Also the otherway around. If for some reason I have disabled the ACA and I use the x20
and the workbench from the motherboard IDE does the workbench reads the clock
from correctly

11 March 2012, 13:45	#1
droopy Posts: n/a	RTC on the a1200 MB ? What would be needed to put an RTC like RF5C01A on the a1200 motherboard ? I guess an oscillator and some additional components. And would it work at all ? I have a spare MB that I just woke up from a mem failure by soldering in some new chip ram circuits and it seems to work fine. But got curious on the space for the RTC next to the ram's and if it is not to much tinkering.....why not..try

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11 March 2012, 16:55	#2
Jope - Join Date: Jul 2003 Location: Helsinki / Finland Age: 43 Posts: 9,861	Check out the A1200 schematics. They have the optional clock circuit drawn into them.

23 July 2017, 12:14	#3
fordav1 Registered User Join Date: Jan 2017 Location: Australia Posts: 84	I realize this is an old thread, but I am not able to find the answer... did anyone actually add the parts onto the A1200 motherboard for the RTC (as per the schematic) and get it working? It's only a couple of dollars in parts and 30 minutes with a soldering iron. I have tons of spare parts here to do it, all I would need to buy is the RTC chip. SMD is no problem for me so I can do the work, but I'm curious if anyone has done it and if it worked?

23 July 2017, 15:15	#5
fordav1 Registered User Join Date: Jan 2017 Location: Australia Posts: 84	excellent, thanks for the info. I'll give it a try.

24 July 2017, 02:48	#6
c4u2sky Banned Join Date: Jul 2017 Location: Ha Noi Posts: 1	thanks. I will try it right after reading this article

05 August 2017, 16:55	#7
fordav1 Registered User Join Date: Jan 2017 Location: Australia Posts: 84	Just a quick update: I've added the parts (minus RTC) and the battery charges as normal. Still waiting for the RF5C01A chips to arrive. I had a hell of a time sourcing them, they are seriously not easy to find now in the SOIC18 package. I ended up going with some random seller on aliexpress who didn't speak English very well.

29 April 2023, 22:33	#9
Charles voner Treadwheel Join Date: Jul 2020 Location: Reading, Mass USA Posts: 5	Hi, I'm reviving this old topic too because somehow my RTC circuit has stopped working and I'm wondering if just adding this chip will it restore my RTC ability. Whatever I do the RTC is not found anymore. I just added a battery to my 1260 and it kept time for 2 weeks then just stopped because it cannot find any clock anymore. Would this chip restore my clock or is something else preventing it from working? The +5v is present on the clockport. Clockport module does not work either although these work on my other Amiga 1200. Thanks.

10 May 2023, 09:53	#10
Mick Registered User Join Date: Jan 2004 Location: Yorkshire Posts: 710	I was going to say that I don't think it's possible since according to the RF5C01A datasheet it is an 18pin part, whereas the A1200 footprint is 20pin and the pins will be messed up. My assumption was that Commodore messed up the circuit/schematics and never bothered to fix it but people claim to have done the mod successfully so maybe Ricoh made it in 20pin too?

10 May 2023, 10:48	#11
Daedalus Registered User Join Date: Jun 2009 Location: Dublin, then Glasgow Posts: 6,334	Regarding the Blizzard 1260's RTC, are you using the correct battery? Some Blizzards were fitted with VL2032s, others with CR2032s, and they're not compatible. Fitting the incorrect type will produce symptoms you describe: the clock working for just a short time. Another issue I've had on one B1260 that was fitted with a CR2032 was the failure of a protection diode on the board, which gave similar symptoms. Motherboard clockport modules will be hit and miss when the accelerator has its own RTC built in. Some will ignore it, some will defer to it, some will produce garbage due to contention when both RTCs are read at the same time.

29 August 2023, 17:44	#12
george7272 Registered User Join Date: Aug 2023 Location: Raleigh/USA Posts: 9	I have an ACA1234 with an rtc module and I was thinking to put one rtc on the motherboard. Do you know if the ACA ignores the rtc from the motherboard when the ACA is active? Also the otherway around. If for some reason I have disabled the ACA and I use the x20 and the workbench from the motherboard IDE does the workbench reads the clock from correctly

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