Search found 306 matches

by sdm
Tue Jun 25, 2019 12:29 pm
Forum: Newbie Help Center
Topic: MMC1 SXROM 32kB WRAM Banking
Replies: 5
Views: 6163

MMC1 SXROM 32kB WRAM Banking

How does 32 kB WRAM work in MMC1 SXROM? It's about access to the whole 32kB - do you have to control four banks of 8kb each ($ 6000-7FFF), or maybe switching $ 8000-FFFF between ROM and RAM?
by sdm
Fri Jun 21, 2019 12:16 am
Forum: Homebrew Projects
Topic: Bushido Bomb
Replies: 4
Views: 7591

Re: Bushido Bomb

Maybe it's worth copying the last line of background tiles from the first screen, to the beginning of the second one? (23A0-23BF copy to 2800-281F). It's about the screen shake effect, in PAL you can see the black bar at the bottom (the first line of tiles appears on the second screen when the scree...
by sdm
Mon Oct 01, 2018 2:56 am
Forum: NESdev
Topic: How do I set up MMC3?
Replies: 17
Views: 11642

Re: How do I set up MMC3?

How many cpu cycles does the switching of mmc3 bank take? it's about 0 8000-9fff bank changed into another one:

Code: Select all

	LDA #%00000110	;6 / 8000-9fff
	STA $8000
	LDA #2		;switch to mmc3 bank 2
	STA $8001
by sdm
Thu Sep 20, 2018 11:57 am
Forum: NESdev
Topic: How do I set up MMC3?
Replies: 17
Views: 11642

Re: How do I set up MMC3?

Ok, but if I do not initiate mmc3 CHR banks at the beginning, but I will use chr banks in the standard order for NROM, then the code will work and mmc3 will read everything in the standard order? ($ 0000 4kb spr $ 1000 4kb bgr, 8kb all for one bank). I did the test code 256KB PRG + 16KB CHR. It work...
by sdm
Tue Sep 18, 2018 5:23 am
Forum: NESdev
Topic: How do I set up MMC3?
Replies: 17
Views: 11642

Re: How do I set up MMC3?

In the previous reset code I inserted the MMC3 init code, which I was thinking is some standard init code for this mapper. Maybe I did something wrong, I do not know. http://forums.nesdev.com/viewtopic.php?f=10&t=12030&start=30#p225789 But I see, you do not need any special mmc3 initialization? Beca...
by sdm
Mon Sep 17, 2018 3:03 am
Forum: NESdev
Topic: How do I set up MMC3?
Replies: 17
Views: 11642

Re: How do I set up MMC3?

ok, everything seems to work, the problem was a small trifle - before LDA% 00000110, there was no "#" character (of course, nesasm3 did not display an error and I missed the problem). I changed the reset code. Works, but is it correct? RESET: sta $E000;Disable IRQs. lda #$01 sta $A000;Horizontal mir...
by sdm
Sun Sep 16, 2018 2:12 am
Forum: NESdev
Topic: How do I set up MMC3?
Replies: 17
Views: 11642

Re: How do I set up MMC3?

I do not want to write about MMC3 in the topic about MMC1. https://forums.nesdev.com/viewtopic.php?f=10&t=12030&start=15 That is why I continue my previous questions about MMC3 here: I am trying to initialize the MMC3 code, but I think I got lost in everything. I try to write an MMC3 code with 256KB...
by sdm
Sat Sep 15, 2018 1:53 am
Forum: Newbie Help Center
Topic: More MMC1 CHR bankswitching woes (On real hardware)
Replies: 39
Views: 12149

Re: More MMC1 CHR bankswitching woes (On real hardware)

To control the direction of screen scrolling (H/V). Unrom equires a soldering iron to switch mirroring. :) I am currently using UNROM-512. However, I have a project in which I use WRAM, and needs mirroring control. Somewhere is a diagram on how to connect WRAM to unrom? (If it requires adding someth...
by sdm
Fri Sep 14, 2018 10:57 am
Forum: Newbie Help Center
Topic: More MMC1 CHR bankswitching woes (On real hardware)
Replies: 39
Views: 12149

Re: More MMC1 CHR bankswitching woes (On real hardware)

Is it correct? reset: ; reset routine moved to $E000-$FFFF sei ; ignore IRQs cld ; disable decimal mode ldx #$40 stx $4017 ; disable APU frame IRQ ldx #$ff txs ; Set up stack ; inx ; now X = 0 ldx #$07 loop: stx $8000 lda mmc3tbl,x sta $8001 dex bpl loop sta $A000 ; set vertical mirroring, or use st...
by sdm
Fri Sep 14, 2018 3:46 am
Forum: Newbie Help Center
Topic: More MMC1 CHR bankswitching woes (On real hardware)
Replies: 39
Views: 12149

Re: More MMC1 CHR bankswitching woes (On real hardware)

Thanks for the explanation.

I also see that MMC3 has switching CHR banks of 1KB, while MMC1 4KB. I have not tried the MMC3 yet, so occasionally I will ask if the MMC3 needs to be specially initiated at the beginning of the code? I am talking about switching on a method similar to UNROM.
by sdm
Thu Sep 13, 2018 10:47 am
Forum: Newbie Help Center
Topic: More MMC1 CHR bankswitching woes (On real hardware)
Replies: 39
Views: 12149

Re: More MMC1 CHR bankswitching woes (On real hardware)

It's probably that I will skip using SUROM. In general, UNROM only lacks WRAM and controls mirroring from the level of the code / program. Apparently it will be better to try MMC3. Is there probably all PRG space available without any problems?
by sdm
Wed Sep 12, 2018 11:36 am
Forum: Newbie Help Center
Topic: More MMC1 CHR bankswitching woes (On real hardware)
Replies: 39
Views: 12149

Re: More MMC1 CHR bankswitching woes (On real hardware)

It's hard for me to understand this, because earlier I used only UNROM, which is very simple. For example. So if I have a code in the last SUROM fixed bank 31: SomeCode: ;code in fixed bank 31 LDA #%00001000 ;select PRG slot 2 STA $A000 ;(***) LDA #$20 ;switch to bank 20 (example) STA MMC1_BankNumbe...
by sdm
Wed Sep 12, 2018 1:47 am
Forum: Newbie Help Center
Topic: More MMC1 CHR bankswitching woes (On real hardware)
Replies: 39
Views: 12149

Re: More MMC1 CHR bankswitching woes (On real hardware)

Thanks. Can anyone explain this to me: "The 256 KB PRG bank selection applies to all the PRG area, including the supposedly "fixed" bank." I guess that if I set the second 256KB of banks, the last bank will also be replaced with a new one? So I need to make a copy of a fixed bank? LDA #%00000000 ;ba...
by sdm
Tue Sep 11, 2018 12:13 pm
Forum: Newbie Help Center
Topic: More MMC1 CHR bankswitching woes (On real hardware)
Replies: 39
Views: 12149

Re: More MMC1 CHR bankswitching woes (On real hardware)

I have a question about switching MMC1 banks when the PRG ROM has 512KB (SUROM). At Nesdev wiki, he writes: https://wiki.nesdev.com/w/index.php/Programming_MMC1 Then to switch PRG ROM banks, load the bank number (0-15) into A and call this subroutine: mmc1_load_prg_bank: sta $E000 lsr a sta $E000 ls...
by sdm
Tue Jun 05, 2018 3:47 am
Forum: Homebrew Projects
Topic: DELETE TOPIC
Replies: 10
Views: 14301

DELETE TOPIC

DELETE TOPIC