A place that you can discuss reproduction of classic titles or "licensed-for-reproduction" homebrew for personal use.
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Kayumba
- Posts: 113
- Joined: Sun Mar 01, 2020 2:36 am
Post
by Kayumba » Thu May 28, 2020 2:39 pm
lidnariq wrote: ↑Thu May 28, 2020 2:21 pm
Have you already made a reproduction without using the 74'74?
yes
lidnariq wrote: ↑Thu May 28, 2020 2:21 pm
If so, what did you do there?
For Hirom
My pin30 of 27C801 (originally A17) connected to pad 44 of PCB (which is A19)
For LoROM
My pin30 of 27C801 (originally A17) connected to pad 45 of PCB (which is A19)
After SWAP BIN method, pin30 of 27C801 digitally became A19.
So when you said :
"the 74'74 should be connected to A19"
My question is to confirm that you are talking about A19 of 27C801 (pin1) or after SWAP BIN method A19 = pin30 ?
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lidnariq
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- Location: Seattle
Post
by lidnariq » Thu May 28, 2020 2:44 pm
The pin that is functionally used as A19, to distinguish between the first half and the second half of the data you programmed.
(that is, pin 30)
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Kayumba
- Posts: 113
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Post
by Kayumba » Thu May 28, 2020 2:48 pm
lidnariq wrote: ↑Thu May 28, 2020 2:44 pm
The pin that is functionally used as A19, to distinguish between the first half and the second half of the data you programmed.
(that is, pin 30)
If so, you talking about
pin30 of 27C801 (originally A17 => became A19 after swap method).
I will try to do some test this week-end.
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Kayumba
- Posts: 113
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Post
by Kayumba » Sat May 30, 2020 4:22 pm
Yes It's WORK!
Thank's.
Here is final diagram of LoROM/HiROM 2in1 games - for Flip-flop 74HC74 and M27C801
This diagram if
for SWAP BIN roms.
If you dont use SWAP BIN method, connect pin9 (Data Output 2) of 74HC74 => to pin1 (A19) of M27C801
Last edited by
Kayumba on Thu Aug 27, 2020 10:19 am, edited 2 times in total.
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Kayumba
- Posts: 113
- Joined: Sun Mar 01, 2020 2:36 am
Post
by Kayumba » Wed Aug 05, 2020 9:08 am
Guys,
One question.
Can I use this diagram on one EPROM 27C322 with 4 games of 8mbit (4x8) stitched to one 32MBIT file?
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Kayumba
- Posts: 113
- Joined: Sun Mar 01, 2020 2:36 am
Post
by Kayumba » Thu Sep 17, 2020 9:47 am
I tried to use the same diagram with not swapped bins (.SMC EPROM).
I just tied
pin1 (A19) of M27C801 to
Data Out 2
But it doesn't work.
It's work only with swapped method .
Whats wrong?
If it's always A19, why its dont work anymore ?
Last edited by
Kayumba on Mon Sep 21, 2020 6:20 pm, edited 2 times in total.
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Kayumba
- Posts: 113
- Joined: Sun Mar 01, 2020 2:36 am
Post
by Kayumba » Sun Sep 27, 2020 4:36 pm
After what I found on the net that other people do.
I Will test this schema and tell you if it will works for M27C801 2in1 HiRom/LoROM, without making SWAP BIN:
