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Author Topic: Internal RTC and 512KB Flash-ROM for Saint's memory expansions (Read 7886 times)

Online gflorez

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #30 on: 2017.February.11. 23:58:51 »
Please Zozo, can you check if the solder points have been correctly selected?
« Last Edit: 2017.February.12. 00:03:49 by gflorez »

Online Zozosoft

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #31 on: 2017.February.12. 07:20:22 »
The /Reset are wrong, it is the /INT.

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #32 on: 2017.February.12. 07:22:15 »
RTC Pin1 corrected?

Online gflorez

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #33 on: 2017.February.12. 11:59:02 »
The /Reset are wrong, it is the /INT.

Ok, disconnected. It is not present on the original RTC board.

RTC Pin1 corrected?


The problem is, when I connect /RD, the EP starts to do odd things. It hangs at cold reset on the SD partitions screen, but only in 10Mhz, so I can reach the flashing letters screen on 4Mhz and then switch to Turbo speed. Also, once in Basic, loading SymbOS on 10Mhz also hangs. I have to switch to 4Mhz, and once loaded, again switch to 10Mhz. But then the mouse wouldn't work on Turbo speed.(we have to talk to Prodatron about that issue...)
 
On this situation, when pin 1 of RTC is connected to +5v(Motorola mode), at cold reset, the SD Reader hangs on the two speeds.

Sometimes on 4Mhz, pressing reset, it jumps to the clock, and other reset makes it jump to the SD partitions screen. But only sometimes.

I think I better will wait for Pear to make his own tests.
« Last Edit: 2017.February.12. 12:02:35 by gflorez »

Online gflorez

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #34 on: 2017.February.16. 13:51:10 »
Ok, disconnected. It is not present on the original RTC board.

I said it very fast... of course /Reset is used on the original project. A 4,7 nF condenser and a 1KOhm resistance give a short GND impulse at power-on. I will try it while other better way is found...

Online gflorez

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #35 on: 2017.February.17. 11:26:04 »
Even easier, /RESET can go directly to Vcc:


Offline Povi

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Re: Internal Real Time Clock
« Reply #36 on: 2019.March.27. 14:46:12 »
Stripes cut.
What kint of tool do you use to cut the stripes?
*** Speicherplatz zu klein

Online gflorez

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #37 on: 2019.March.27. 15:04:01 »
You do mean to cut cooper tracks on a circuit, don't you?

I use a similar machine than this:



There are little milling tips that can be used as a pencil, with enough precision.

Offline jakoa

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #38 on: 2021.April.16. 10:27:07 »
Even easier, /RESET can go directly to Vcc:

(Attachment Link)
I am nut sure if the problem still exists, but I am also working on an internal board with an RTC.
I use the DS12885 chip because of the size and a possibility for battery replacement.
I was also struggling with the operation and at the end I found an error, maybe it was also in your case.
The input Vbat cannot be left open. Either an external battery should be connected or it has to be connected to GND.
Leaving this pin open, the chip does nothing. (The applied battery case creates this connection if no battery is inserted.
After the connection on the ground it worked fine for me.
The pin1 MOT is connected to Vcc,
The Pin 13 -CS get the RESET signal (inverted -RESET).

Online gflorez

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #39 on: 2021.April.16. 11:41:55 »
Great!

I left my plan to install the internal RTC because I did not found any way to put the clock to work.

Thanks a lot. I will try your fix in due time...

Offline jakoa

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #40 on: 2021.April.16. 13:26:20 »
If you need I can send you the actual timing analysis, but it should also work for you:
RESET is high,
CS is normally continuously low.
Address is written into the rising edge of AS. (R/-W is low),
Data is written (after the address is set) on the rising edge of DS (R/-W is low), or
Data is read (after the address is set) on the rising edge of DS (R/-W is high).

Online gflorez

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #41 on: 2021.April.29. 11:16:30 »
I have just found my old hand made PCB:

27131-0

I can't remember now what I did.... so I will read this thread thoroughly.
« Last Edit: 2021.April.29. 11:22:12 by gflorez »

Offline jakoa

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #42 on: 2021.April.30. 14:16:34 »
I assume the GAL (probably) is responsible for the address (FEh and FFh) decoding and for the control signals (AS, DS, CS, G, DIR).
The empty socket should be waiting for the 74LS245 transceiver. :-)

Online gflorez

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Re: Internal RTC and 512KB Flash-ROM for Saint's memory expansions
« Reply #43 on: 2021.April.30. 14:36:16 »
Yes, that is. The Gal and the 245(I have re-used it on another project....)

I will search for the GAL formulas on an old laptop this weekend.