Search found 881 matches

by krzysiobal
Mon Jun 14, 2021 11:23 pm
Forum: General Stuff
Topic: Fake low power KM62256BLS SRAM from aliexpress
Replies: 2
Views: 135

Fake low power KM62256BLS SRAM from aliexpress

I was searching for a low power (suitable for battery backup) SRAM, in a shrink DIP-3, not as more common DIP-6 package. The only that I know so far are KM6264BLS and KM62256BLS, the latter is preferred as it is 32kB. I had previously both of them and was quite happy. I found one on aliexpress for r...
by krzysiobal
Mon Jun 14, 2021 1:43 am
Forum: NES Hardware and Flash Equipment
Topic: Why $4017.D0 is present in famicom's EXP port?
Replies: 7
Views: 3667

Re: Why $4017.D0 is present in famicom's EXP port?

Shared with Joypad 2, it can be connected with digital level input, such as tape driver, or microphone input You can also define an address from $4020 to $5fff instead of port $4017, and expand the function through the cartridge slot, or install an earphone jack on the cartridge board. That's simil...
by krzysiobal
Sat Jun 12, 2021 12:21 pm
Forum: NES Hardware and Flash Equipment
Topic: HVC-STROM
Replies: 12
Views: 4039

Re: HVC-STROM

Schematics:
by krzysiobal
Fri Jun 11, 2021 12:52 pm
Forum: Reproduction
Topic: iNes mapper 76 with 256 KiB?
Replies: 2
Views: 351

Re: iNes mapper 76 with 256 KiB?

What parts are available? Decoder: 74139 / 74138 Latch: 74161 / 74670 / 74273 / 74174 / 7474 I think you would need around 4-5 chips, this is my opinion not worh doing that way. Single PAL16L8 can do the trick. I made two PAL16L8 fusemaps (don't forget to connect externally LOOPIN and LOOPOUT): *fir...
by krzysiobal
Thu Jun 10, 2021 1:31 pm
Forum: NES Hardware and Flash Equipment
Topic: Holy Diver works on Famicom but not on NES
Replies: 8
Views: 758

Re: Holy Diver works on Famicom but not on NES

Holy Diver also contains a 74HC245 to compensate for a slow CHR ROM chip. I don't know what this exactly mean, because I did not analyz the PCB but to my best understanding - data bus goes thru that buffer, CHR-ROM is always enabled and the buffer is controlled by PPU A13 (or PPU RD?) which can go ...
by krzysiobal
Thu Jun 10, 2021 5:03 am
Forum: NES Hardware and Flash Equipment
Topic: Big RAM on FME-7: I have a test ROM
Replies: 31
Views: 35994

Re: Big RAM on FME-7: I have a test ROM

**Although FME-7 has the bank switching capability of PRG RAM, no game relies on it. Why you and author of the wiki's article consider it as something special? What would you expect on the PRG lines without that "special feature" when accesing $6000 when RAM is enabled? Zeroes? Ones? Tri-state? The...
by krzysiobal
Wed Jun 09, 2021 1:48 pm
Forum: General Stuff
Topic: Becoming an FPGA Engineer
Replies: 48
Views: 4687

Re: Becoming an FPGA Engineer

Instead of trying non synthetisable command like "delay", try searching if your FPGA have built in feature for programmable delay. For example - the cheap popular EPM240 has and it can be turned as follows: pd.png BTW. The signal initial value assignment is not synthetisable in al chips, you should ...
by krzysiobal
Tue Jun 08, 2021 6:13 pm
Forum: Reproduction
Topic: NC pins - connect to GND or VCC
Replies: 10
Views: 939

Re: NC pins - connect to GND or VCC

Additionally, if you're projecting a PCB that will be manufactured in many copies, have in mind that for example A21 for 29LV320 (4MB) = NC, but for 29LV640 (8 MB) it is normal input pin. At some point of your manufacturing you might consider switching from 320 to 640 (because of price or lack in st...
by krzysiobal
Tue Jun 08, 2021 5:33 am
Forum: NESemdev
Topic: Oeka Kids Tablet
Replies: 7
Views: 6823

Re: Oeka Kids Tablet

Russians shared photos of this tablet (google translate engine does not work well with photos on their site) https://translate.google.com/translate?hl=&sl=ru&tl=en&u=http%3A%2F%2Fwww.emu-land.net%2Fforum%2Findex.php%2Ftopic%2C84560.0.html https://obrazki.elektroda.pl/1420517000_1623154409_thumb.jpg ...
by krzysiobal
Fri Jun 04, 2021 9:50 am
Forum: Reproduction
Topic: iNes mapper 75 with 256KiB PRG
Replies: 8
Views: 840

Re: iNes mapper 75 with 256KiB PRG

Try this:
by krzysiobal
Thu Jun 03, 2021 4:57 pm
Forum: NESdev
Topic: Scanlines to CPU cycles
Replies: 4
Views: 719

Re: Scanlines to CPU cycles

What about rom offset $6fe86 - I see around 368 zeros here, maybe you can use it and make some kind of compression of your table (calculate only value for even scanlines, and the one for odd will be average of two neighbours? If not PRG ROM, then maybe CHR? I see there are a lot of identical tile-bo...
by krzysiobal
Thu Jun 03, 2021 8:47 am
Forum: General Stuff
Topic: Why did Codemasters make so many version of their cartridges?
Replies: 1
Views: 591

Why did Codemasters make so many version of their cartridges?

Excuse me my ignorance, but why did Codemasters make so many different versions of their cartridges? For example: Quattro Sports 1a) Aladdin NES version: https://obrazki.elektroda.pl/2797742700_1622734165_thumb.jpg https://obrazki.elektroda.pl/6225165300_1622734176_thumb.jpg https://obrazki.elektrod...
by krzysiobal
Wed Jun 02, 2021 10:14 am
Forum: NES Hardware and Flash Equipment
Topic: Sunsoft 5B pin 18
Replies: 8
Views: 863

Re: Sunsoft 5B pin 18

Here is my summary of what is my observations: * this pin does not change behavior of PRG/CHR/IRQ functionality at all (Gimmick work fine with its being low, just external audio is not audible) * when this pin is LOW, any writes to $e000 does not have any effect * any writes to $c000 when this pin i...
by krzysiobal
Tue Jun 01, 2021 7:36 am
Forum: NES Hardware and Flash Equipment
Topic: City Figher 4 with ext audio (Mapper 266)
Replies: 17
Views: 8727

Re: City Figher 4 with ext audio (Mapper 266)

Help,I have been working on the verification of this cartridge during this period of time, but I still haven't succeeded. I hope you can help me to describe the logic of (CPU_R_nW, CPU_ROMSEL, CPU_A14, CPU_A13, CPU_A12) and (VRC4_900C). I use some logic chips to realize it.I think that's the proble...
by krzysiobal
Mon May 31, 2021 10:15 am
Forum: NES Hardware and Flash Equipment
Topic: Aladdin Deck Enhancer / CCU_v2.00 CF30288 pinouts
Replies: 12
Views: 7040

Re: Aladdin Deck Enhancer / CCU_v2.00 CF30288 pinouts

I applied all your suggestions and ended with something like this: aladdin deck enhancer 1.1.png aladdin deck enhancer 2.0_sch.png PIC15C54C is listening to CPU data bus and probably feeding some instructions to the CPU and causing short-circuits of VCC to GND, using the mosfet, to glitch the CIC, j...