Search found 511 matches

by aquasnake
Tue Sep 26, 2023 1:42 am
Forum: NES Hardware and Flash Equipment
Topic: Is the Everdrive safe to use on the NES/Famicom?
Replies: 5
Views: 1621

Re: Is the Everdrive safe to use on the NES/Famicom?

NMOS is more similar to the TTL structure, which is also a structure of 1 transistor+1 pull-up resistor (pull-up resistor optional, if not integrated, it is the OD output), but the difference is that the low level output of NMOS is closer to 0V CMOS is a pair of transistor structures (PMOS+NMOS comb...
by aquasnake
Mon Sep 25, 2023 9:22 pm
Forum: NES Hardware and Flash Equipment
Topic: Is the Everdrive safe to use on the NES/Famicom?
Replies: 5
Views: 1621

Re: Is the Everdrive safe to use on the NES/Famicom?

In order to prevent ESD, early processes typically integrated a Schottky diode inside the IO to protect it and ensure its maximum withstand voltage not exceeding vcc+0.7v The integration of the new process is not Schottky diodes, but TVS, which is two reverse series connected to form a group. TVS al...
by aquasnake
Mon Sep 25, 2023 9:01 pm
Forum: NES Hardware and Flash Equipment
Topic: Is the Everdrive safe to use on the NES/Famicom?
Replies: 5
Views: 1621

Re: Is the Everdrive safe to use on the NES/Famicom?

In fact, only the CMOS level is rail to rail. The high level of TTL is approximately 0.7VCC (5V voltage corresponds to an output of about 3.5V, while the high level decision is 2.5V), because TTL has strong suction current (corresponding to L level) and weak pull-out current (corresponding to H leve...
by aquasnake
Sun Sep 24, 2023 10:22 pm
Forum: NES Hardware and Flash Equipment
Topic: Kazzo USB rom dumper / dev cart programmer
Replies: 760
Views: 503738

Re: Kazzo USB rom dumper / dev cart programmer

for 7-in-1 (NS03), NES2.0 ID: #331, UNIF ID: BMC-12-IN-1 board <- { //change to 331 after dumping mappernum = 130, ppu_ramfind = false, vram_mirrorfind = false, cpu_rom = { size_base = 4 * mega, size_max = 4 * mega, banksize = 0x4000 }, ppu_rom = { size_base = 4 * mega, size_max = 4 * mega, banksize...
by aquasnake
Sun Sep 03, 2023 9:47 am
Forum: NES Hardware and Flash Equipment
Topic: RAM brands and Jailbars
Replies: 2
Views: 1297

Re: RAM brands and Jailbars

Different SRAMs have different slew rates for output, and excessively fast slew rate typically generates signal reflections (with a large amount of higher harmonics) on the bus. The solution is to connect 100ohm of resistors in series on the bus
by aquasnake
Sun Sep 03, 2023 9:10 am
Forum: NES Hardware and Flash Equipment
Topic: PRG-RAM decoding circuitry - problems
Replies: 8
Views: 7357

Re: PRG-RAM decoding circuitry - problems

For TTL output, a DRC circuit is required because TTL has strong low-level output and weak high-level output (with only one NPN transistor and pull-up resistor couples inside). To ensure a fast rising edge of SRAM_CE, a diode is needed to accelerate the jumping current. For CMOS output, it has stron...
by aquasnake
Fri Sep 01, 2023 11:34 am
Forum: NES Hardware and Flash Equipment
Topic: BF9096 (camerica mapper 232) - invalid pinout description
Replies: 7
Views: 7382

Re: BF9096 (camerica mapper 232) - invalid pinout description

I reviewed this again, and for mapper 232, different dump settings can obtain different data composition orders If the bank where the menu located is placed in the last 64K space, there can be another expression: cpu_addr_out[17:16] = ~outer[4:3]; BF9093 = mapper 2 BF9097 = mapper 71 BF9096 = mapper...
by aquasnake
Fri Aug 18, 2023 5:48 am
Forum: NES Hardware and Flash Equipment
Topic: 632 in 1
Replies: 18
Views: 4284

Re: 632 in 1

no emulator can support an unknown mapper, but probably could run the first 128K menu by forcibly modifying the MAPPER ID to some else(COOLBOY??)
by aquasnake
Fri Aug 18, 2023 5:41 am
Forum: NES Hardware and Flash Equipment
Topic: Is stacking cartridges bad for the Famicom?
Replies: 6
Views: 1616

Re: Is stacking cartridges bad for the Famicom?

I think the main potential issues are power supply and transmission line length (attenuation) issues
by aquasnake
Sat Aug 05, 2023 1:58 pm
Forum: NES Hardware and Flash Equipment
Topic: 632 in 1
Replies: 18
Views: 4284

Re: 632 in 1

Interesting, first time see such multicart with flash configured in 16 bit mode, letting the mapper-blob to read/write 16 bit data words. No idea why it is that way, this flash chip has ability to be wired in both 8/16bit mode, but it is permanently wired to 16 bit. Maybe this could improve speed o...
by aquasnake
Sat Aug 05, 2023 10:35 am
Forum: NES Hardware and Flash Equipment
Topic: 632 in 1
Replies: 18
Views: 4284

Re: 632 in 1

632_in_1_cover_fixed.png
278_in_1_cover_fixed.png
by aquasnake
Wed Jul 05, 2023 5:22 am
Forum: NESdev
Topic: 4-in-1 Multirom help
Replies: 11
Views: 2071

Re: 4-in-1 Multirom help

It only costs about $5 and you can find Chinese merchants from Aliexpress to customize it for you
by aquasnake
Wed Jun 28, 2023 10:04 am
Forum: NES Hardware and Flash Equipment
Topic: The maximum number of mappers that can be accommodated by epm240
Replies: 19
Views: 3032

Re: The maximum number of mappers that can be accommodated by epm240

Wiki says:"When writing is disabled ($4089.7), reading anywhere in 4040-407F returns the value at the current wave position." I set the read breakpoint between $4040- $407F, but the program did not stop, indicating that the reading is not accessed through the CPU addresses. It should have ...
by aquasnake
Mon Jun 26, 2023 8:31 pm
Forum: NES Hardware and Flash Equipment
Topic: The maximum number of mappers that can be accommodated by epm240
Replies: 19
Views: 3032

Re: The maximum number of mappers that can be accommodated by epm240

FDS shouldn't require dual-ported RAM - the wavetable RAM can't be accessed by the CPU and the audio at the same time. It is true that reading and writing wavetable are not the same in time, but also not the same(bus) in space. Emulating pseudo DPRAM using SRAM externally is also more complex, so i...
by aquasnake
Mon Jun 26, 2023 8:15 am
Forum: NES Hardware and Flash Equipment
Topic: The maximum number of mappers that can be accommodated by epm240
Replies: 19
Views: 3032

Re: The maximum number of mappers that can be accommodated by epm240

A few days ago, I updated the design and added the implementation of Sunsoft-5B and VRC6 expansion audio. All I need to do is adding an 8-bit DAC. The verilog implementation does not take up much LEs, with three 16-bit counters and a 6-bit adder. The EPM570 can also include both expansion audio whil...