Search found 125 matches

by doragasu
Sat Jan 09, 2016 1:19 pm
Forum: Hardware
Topic: Questions about clock signals available on the cart slot
Replies: 5
Views: 2845

Re: Questions about clock signals available on the cart slot

Thanks, everything clear now!

You really know your stuff!!!
by doragasu
Sat Jan 09, 2016 1:17 pm
Forum: Hardware
Topic: Question about B31 (aka #TIME) cart pin
Replies: 14
Views: 4454

Re: Question about B31 (aka #TIME) cart pin

I was wondering if #TIME signal behaves exactly like a #CE or has other behaviour that justifies its weird name, so I wired a cheap 8 Channel, 24 MHz logic analyzer and soldered some wires. Then made a program that continuously reads 0xA13CA. I was surprised by the result, to the point that I'm wond...
by doragasu
Fri Jan 08, 2016 8:04 pm
Forum: Hardware
Topic: Questions about clock signals available on the cart slot
Replies: 5
Views: 2845

Re: Questions about clock signals available on the cart slot

Thanks for the explanation!

There's just one thing that isn't yet clear to me. The clock frequency is tied to the video mode or to the console?

A PAL console with the 60 Hz mod, can generate 7.67 MHz clock signal?
by doragasu
Wed Dec 30, 2015 5:31 pm
Forum: Hardware
Topic: Questions about clock signals available on the cart slot
Replies: 5
Views: 2845

Questions about clock signals available on the cart slot

AFAIK, on the cartridge slot there are two clock signals available: - CLK (pin B19). - HS_CLK (pin B15). I couldn't find too much information about them. CLK is supposed to be the main 68k clock, so I suppose it's 7.67 MHz when working in NTSC mode, and 7.61 MHz when working in PAL mode. I have read...
by doragasu
Fri Nov 13, 2015 8:04 am
Forum: Hardware
Topic: Question about B31 (aka #TIME) cart pin
Replies: 14
Views: 4454

Re: Question about B31 (aka #TIME) cart pin

Thanks!

I just wanted to make sure.
by doragasu
Thu Nov 12, 2015 2:56 pm
Forum: Hardware
Topic: Question about B31 (aka #TIME) cart pin
Replies: 14
Views: 4454

Re: Question about B31 (aka #TIME) cart pin

I have another question about mapping things using #TIME signal. Do I have to assert the #DTACK signal for data reads? IFAIK this is not needed for logic mapped under the first 32 Mib address range, but I was wondering if I'll experiment a hardware lock or any other undesired effect if reading from ...
by doragasu
Thu Oct 15, 2015 6:53 am
Forum: Hardware
Topic: Interfacing CMOS 3.3V logic
Replies: 15
Views: 5775

Re: Interfacing CMOS 3.3V logic

OK, I'll go the safe route and use transceivers. Thanks for the help!
by doragasu
Sat Oct 10, 2015 10:13 am
Forum: Hardware
Topic: Interfacing CMOS 3.3V logic
Replies: 15
Views: 5775

Re: Interfacing CMOS 3.3V logic

The PCB cart design from Krikkzz I linked above, is very recent (it's dated december 2014 on the PCB), and he uses resistors.
by doragasu
Fri Oct 09, 2015 7:00 am
Forum: Demos
Topic: Garoudan - Currently WIP
Replies: 3
Views: 2295

Re: Garoudan - Currently WIP

Great work nevat! Good to see this version is progressing nicely!
by doragasu
Fri Oct 09, 2015 6:46 am
Forum: Hardware
Topic: Interfacing CMOS 3.3V logic
Replies: 15
Views: 5775

Interfacing CMOS 3.3V logic

Has anybody info about VOH, VOL, VIH, VIL (with max and min) for the cartridge lines? Could 3.3V CMOS devices be interfaced without the need of transceivers such as 74LVC162245? Maybe adding just some series resistors to limit current on clamping diodes (if VOHmax is higher than 3.3V) would do the t...
by doragasu
Wed Oct 07, 2015 3:06 pm
Forum: Hardware
Topic: Question about B31 (aka #TIME) cart pin
Replies: 14
Views: 4454

Re: Question about B31 (aka #TIME) cart pin

Thanks for the replies!

Just to complete the topic, is there detailed information about the timing of this signal? Is it asserted the same time as e.g. #C_CE?
by doragasu
Sun Oct 04, 2015 5:55 pm
Forum: Hardware
Topic: Question about B31 (aka #TIME) cart pin
Replies: 14
Views: 4454

Question about B31 (aka #TIME) cart pin

I have read here that B31 (#TIME) line is active (low) on accesses to 0xA13000 -> 0xA130FF range. Is this true? Could I wire this #TIME line to a battery backed 256 byte SRAM chip #CE signal, and use it to save/load games without conflicting with the ROM chips? (of course also A1~A8, D0~D7 and #LDSW...
by doragasu
Wed Jun 03, 2015 1:07 pm
Forum: Hardware
Topic: Cartridge interrupts?
Replies: 4
Views: 3308

Thanks for the information. Maybe setting an HBLANK interrupt each N lines, may do the trick without wasting too many CPU cycles. Too bad SEGA didn't include an interrupt line... even NES and Master System had it, and it's extremely useful for in-cart peripherals.
by doragasu
Wed Jun 03, 2015 9:22 am
Forum: Hardware
Topic: Cartridge interrupts?
Replies: 4
Views: 3308

Not even Z80 ones? If the answer is a big NO, is there a way to automatically trigger DMA transfers when a cart pin changes? (I suppose I'll get another NO here). I want to connect a 16C550 UART to the bus, and if I can neither use interrupts nor automatic DMA, bit rate will be greatly limited (beca...
by doragasu
Tue Jun 02, 2015 8:20 pm
Forum: Hardware
Topic: Hmmmm.......?
Replies: 25
Views: 10847

Looks extremely kickass!!!