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some of you might remember I was working in a expansion port cartridge last year... I'm almost finishing my project, after some months during which I did have no time to work on. I manged to flash a rewritable flash cartridge (game cartridge with mask ROM replaced by a 29F800 16 bit Flash...

Sorry to take so much to answer, but I had some problems, and had to leave my projects a side for a while. I love it. This logic analyzer is great. The only drawback is 2048k samples per channel. But has lots of features and works great. Please, if you have any question, ask me.

Here is a little fragment of my work on Genesis. As I already said some time ago, I'm working on a expansion cart, which boots up a BIOS ROM. I managed to boot 256Kb games. Now, I added an IDE conector, and I'm able to test read CF cards. I created a file system, and a PC software to write to...

About Pinchy's gens cart I know which post you're talking about. He's using a FPGA as DRAM controller..

About Pinchy's gens cart Have you seen Pinchy's DRAM cart.. I'm impressed. He's done great job with the saturn and now genesis. I wonder if anyone knows any details on the implementations. I'm trying to contact with Pinchy but he does not answer... :(

I'm making simple rewritable carts for a while. But they were quite rudimentary. Now I'm planning building a 2Mbytes cart for Genesis. I'll use TSOP or SO flash memory chips, and original cart with SRAM, to replace ROM. To build a cart from scratch, you need 2 side photosensitive PCB, TSOP...

Example of this sequence: (Add with carry from memory to a register, then update memory location) SNES 65c816 (supposing one operand is already in acumulator) ADC #$xxxxxx STA #$xxxxxx GENESIS 68k (Supposing one operand is already in Dn register) ADD.w #$xxxxxx, Dn MOVE.W Dn...

Yes, after adding, and storing data in a register, it takes 16 cycles to store in memory (do a move.w Dn, #$xxxxxx) As it is an absolute long addressing access, it needs 3 reads, in order to fetch instruction (absolute short, would require 2 reads), and another write in order to store the data...

I’m tring to write a comparative between MC68000 and 65c816 performance. I always asumed that motorola’s was far more powerful than SNES CPU. But I begin to doubt. :huh According to MC68000 documentation, and 65c816 docs: For a 16 bits add with carry instruction: Register to register...

Hi I'm about to upload a web page with info about my genesis expansion port cart. But I had a problem two days ago. I'm trying to map some ports to it, to control an external device. But when I was doing debuging, my Genesis died. It was working. It was actually working when I was debugging...

I want to make a list of items for the user to choose. I have done a cursor, that you move with the direction pad, to go up and down. But I wonder how could I make the rest efficiently. I I write, let's say, 10 items in the list (that is not a problem), how can I do to refresh the items?? I...

Yes, I was thinking on making that. That is waht I do for more complex projects, I just wanted to make something easy for now, but it definitively is the best choice. By the way, do you know what happends if a nes VBlank int comes while running the last VBlank int handler??

That's what I do. I poll once per VBlank. BUT, when I detect a button pressed, I call a Wait for all button are release in a loop before going on. this is to get rid of repetitive button detection. I just want to detect once per button pressed. then you need to release the button and press...

I use the following routine to poll pad status GetPAD: clr.l d0 clr.l d1 move.b #$40,$A10003 move.b $A10003,d0 andi.b #$3F,d0 move.b #$00,$A10003 move.b $a10003,d1 andi.b #$30,d1 lsl.b #2,d1 or.b d1,d0 not.b d0...

Hi, I’m doing some tests while cart high, booting code from expansion port. And there’re some differences. I thought /ROM was a $000000-$03FFFF strobe, but it isn’t. It is a $000000-$1FFFFF strobe. /ASEL pulses are shorter than /ROM’s /CAS_2 and /FDWR are even shorters. Also, /CAS_2...

As far as I know, and Charles McDonnald confirmed me, /ROM signal in expansion port is active only in range $000000-$03FFFF... Umm.. I should check this with logic analyzer to make sure, but I think this scheme I'm thinking of to address spaces above $03FFFF is the one used by Sega for...

/CAS-0 for ROM /OE /ROM for ROM /CS I plan to enable the new device when /ROM = 1 /ASEL = 0 This means valid data in the bus, but above $03FFFF. ROM will be disabled.

Really, it will be mapped at $040000-$07FFFF, and then mirrored. So it is power of 2. I'll have a look with a logic analyzer at /CAS-0, and see if it asserts only for read access, then it will be great.

Ok, I'm working on my expansion port cart (I'll post pictures and data soon). So far, it has a ROM mapped $000000-$03FFFF (256Kb) Now I want to map a device $040000-$3FFFFF But this I need to read and write. As I'll be using only low byte accesses, I'll do byte accesses to odd addresses...

Yes, I know about serial EEPROMS. What I never heard about is FRAM.. neither find much info in google. Is it just the same as any SRAM?