Search found 583 matches

by Mask of Destiny
Mon Feb 11, 2019 6:48 pm
Forum: Blabla
Topic: 68000 Arcade systems programming
Replies: 14
Views: 977

Re: 68000 Arcade systems programming

They're not on his site anymore, but Charles MacDonald actually wrote docs describing various Sega Arcade boards and they are archived at various places:
Pre-System 16
System 16B
System 18
System C2
X-Board
System 24
by Mask of Destiny
Sun Jan 27, 2019 3:45 am
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 14
Views: 1143

Re: BlastEm 0.6.0

Cool. Yeah, that definitely finds the rom.db. It's probably how I built the project, but it doesn't actually show anything when I run a rom. I get a blank screen and the following error: "Failed to open shader file default.v.glsl for reading" Shaders are expected to be in the "sharers" subdirectory...
by Mask of Destiny
Thu Jan 24, 2019 10:00 pm
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 14
Views: 1143

Re: BlastEm 0.6.0

Sounds good, I'll give it a go later on. BTW, love the debugging modes on this. This should be very handy! Glad you like them. I have pushed some changes to allow for building a more standard filesystem hierarchy friendly binary. If you want to try it out, grab tip from the repo and build with the ...
by Mask of Destiny
Mon Jan 14, 2019 8:47 pm
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 14
Views: 1143

Re: BlastEm 0.6.0

Installing in Linux is kind of awkward, since it is not looking in standard locations for config files. /etc/, ~ (according to README). The location of blastem.cfg is standard for a per-user config file. It is true that my tarball is a self-contained package rather than something that's designed to...
by Mask of Destiny
Mon Jan 07, 2019 6:30 pm
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 14
Views: 1143

Re: BlastEm 0.6.0

There's only one little issue for me with it: checkboxes look like they mean the opposite they should, ie. a black checkbox means "enabled", which seems odd. Yeah, the default checkbox style is one of my biggest beefs with Nuklear. I'll have to see if there are any easy tweaks that can make it a bi...
by Mask of Destiny
Sat Jan 05, 2019 9:09 pm
Forum: Megadrive/Genesis
Topic: 68K inner workings
Replies: 3
Views: 436

Re: 68K inner workings

Have you had a look at the 68K patents? Looks like you've managed to figure out a lot from the schematic, but the US4325121 patent specifically has a lot of information about how the microcode/nanocode works and includes micro/nanocode listings for a pre-release version of the processor which might ...
by Mask of Destiny
Fri Jan 04, 2019 6:04 pm
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 14
Views: 1143

Re: BlastEm 0.6.0

v0.6.0 ended up being kind of buggy due to an abbreviated QA cycle. v0.6.1 fixes a number of issues and is now available here
by Mask of Destiny
Tue Jan 01, 2019 8:43 am
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 14
Views: 1143

BlastEm 0.6.0

I've released a new version of my Gen/MD emulator. Big change this time is a new UI using the Nuklear toolkit. Unlike the old UI, you can actually change almost all config options through the UI rather than editing the config file. Of interest to developers are some improvements to the VDP debug vie...
by Mask of Destiny
Sat Dec 01, 2018 4:13 am
Forum: Exodus
Topic: Genesis 68K bus timing
Replies: 6
Views: 1019

Re: Genesis 68K bus timing

Here's a small collection of captures of various types of bus interactions. They are in Open Logic Sniffer Project format. Explanations below: direct_color_dma.olp - Capture of the start of 68K->VDP DMA from one of Chilly WIlly's Direct Color DMA samples (note that !CAS and !RAS here refer to VRAM !...
by Mask of Destiny
Fri Nov 30, 2018 6:33 pm
Forum: Exodus
Topic: Genesis 68K bus timing
Replies: 6
Views: 1019

Re: Genesis 68K bus timing

I am searching hardware level information about the interface with the 68K. Do you know if anybody performed logic analyzer traces showing the timing of the clock and the bus control signals? Yes. 68K clock is always the master clock/7 (unless you count the Teradrive which can also run the CPU at 1...
by Mask of Destiny
Tue Nov 20, 2018 7:30 pm
Forum: Megadrive/Genesis
Topic: Looping access from 68K and Z80
Replies: 25
Views: 1856

Re: Looping access from 68K and Z80

My breakout boards cam it but sadly the pads for the pins on the chip were just a tad too short. New boards ordered but with the US holiday coming up it’ll be 10-14 days before I get them back. In the meantime, I found a semiconductor seller that had some genesis chips in stock so I picked up a cou...
by Mask of Destiny
Thu Oct 11, 2018 7:12 pm
Forum: Megadrive/Genesis
Topic: Bus Arbiter and IO Chip Access
Replies: 28
Views: 2863

Re: Bus Arbiter and IO Chip Access

It would be interesting to verify is there are any differences regarding EDCLK between MD VA1 and late rmodels since it seems VA1 (and likely VA0) is using an earlier version of 315-5345 chip (see 315-5339 description here: http://www.tmeeco.eu/SMD/MD1VA1_315-5339.jpg) which does not use VCLK (and ...
by Mask of Destiny
Thu Oct 11, 2018 7:18 am
Forum: Megadrive/Genesis
Topic: Bus Arbiter and IO Chip Access
Replies: 28
Views: 2863

Re: Bus Arbiter and IO Chip Access

EDCLK: This signal is 0/floating (wasnt a very clean 0) when /SRES, /M3 or /HSYNC are asserted(0). Otherwise it seems to be MCLK/4. (I tested with a 5k signal. Got a 1.25K out. I thought this this should /5, maybe it doesn't like the slow speed?) Does not seem to be affected by anything else. It sh...
by Mask of Destiny
Wed Oct 10, 2018 6:42 pm
Forum: Megadrive/Genesis
Topic: Bus Arbiter and IO Chip Access
Replies: 28
Views: 2863

Re: Bus Arbiter and IO Chip Access

Did some probing on my model 1 va2. It has a 5308 arbiter, a 5309 IO chip and a 5345. For what it's worth, we have the schematics for the VA3 . Main difference from your VA2 is that the 5345 (EDCLK generator, probably just a PAL or GAL) has been integrated into the bus arbiter (5308) and given the ...
by Mask of Destiny
Tue Oct 09, 2018 11:48 pm
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 26
Views: 2858

Re: Cart Design Questions

When writing 8Bit numbers to even addresses, is pin B28 (lower byte write) taken low and pin B29 left high, and for odd addresses B28 is left high and B29 is taken low? Or visa versa? Or does it work differently? !LDSW (B28) goes low (which is the "active" level) for writes to odd addresses and !UD...