Search found 74 matches

by themrcul
Thu Jun 20, 2019 12:17 am
Forum: Demos
Topic: Foxyland
Replies: 1
Views: 139

Re: Foxyland

I think the artwork in this game is really nice Mixail. The thoughtful use of colours and clever reuse of tiles is well done.
I also love how the trees rustle when the player runs past them.
Great work and good luck with your project!
by themrcul
Tue Jun 04, 2019 10:36 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Thanks HardwareMan that's what I thought - I'll need the efficiency of a step-down regulator rather than a linear regulator. I'll fix up the schematic. Sadly the only parts I found that had the parameters I want is in a WFDFN package, so I'll need to use a hot air gun for the first time to get it on...
by themrcul
Tue Jun 04, 2019 4:11 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Great, thanks for that. I have dropped the /AS line and am using /CAS2 now. I have finished the first version of the schematic now (with a linear power regulator for voltage regulation), ready for drawing a PCB layout from. You guys have been so helpful to me for this project. I am in your debt. One...
by themrcul
Mon May 27, 2019 7:00 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Ok, so from what you guys have written at the end of this thread: Gen Cart Pinout http://gendev.spritesmind.net/forum/viewtopic.php?f=13&t=517&start=15 /AS is not asserted for DMA, so for my purposes it is useless. So I may as well connect: /CEO /CAS0 /CAS2 /WRL This should give me enough to go with...
by themrcul
Mon May 27, 2019 2:59 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Thanks guys. Interesting idea to use /CAS2 HardWareMan. The EEPROM I am thinking of using (S29GL032N90TFI040) has a stated total access time of 110ns (this is for random access, not sequential page accesses) - do you think that 110ns is enough time for the EEPROM to be able to get the data if listen...
by themrcul
Sun May 19, 2019 5:15 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Ok, so I will need to route the Ready/Busy line from the EEPROM through the CPLD to /DTACK, and tri-state the /DTACK line when in normal operation (ie when the PCB is being used in a Mega Drive) but when the CPLD knows it is being written to via the EEPROM writing device it can switch operation of t...
by themrcul
Fri May 17, 2019 11:59 pm
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Thanks very much Chilly. Just so I understand what is going on electrically: The EEPROM will expect the line to drift high with a pull-up resistor. The MD expects the signal to be low to signify "ready". If the line from the EEPROM is hooked up to the MD directly *without* a pull-up resistor to 3.3V...
by themrcul
Fri May 17, 2019 2:55 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Hey fellas, I've been progressing with the design, and I've gone back and forward about needing a CPLD or FPGA for the design to work. After a lot of thought and research I have come to the conclusion that everyone else was right from the beginning - I will need a CPLD or FPGA if I am hoping to retr...
by themrcul
Wed May 15, 2019 11:49 pm
Forum: SGDK
Topic: Sega Genesis Dev Kit (SGDK)
Replies: 789
Views: 343156

Re: Sega Genesis Dev Kit (SGDK)

Thanks for your continued and great efforts Stef. I'm looking forward to getting my code base up to date with the new version you have released!
by themrcul
Wed Oct 10, 2018 5:39 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

You guys are amazing, thanks. How do you know all these things!? Anyway, so if my interface between the MD and the ARM chip is 8bit, I can just hook up the lower 8 data lines, and hook the write high/write low to an AND gate, so that 0V = WRITE, 5V = READ. The ARM chip I am looking at now is the ATS...
by themrcul
Wed Oct 10, 2018 12:39 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Awesome, thanks heaps Mask.
Just to confirm, for 8bit writes, only the first 8 data lines are used, is that correct? Do the upper 8 data lines (D8-D15) go to 0V? Or is their state indeterminate?
by themrcul
Tue Oct 09, 2018 9:25 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Hi everyone, 8 weeks ago my wife and I had our first baby so things have been very busy but I have been planning and thinking about this project lots regardless! I now have a question about the pins on the cart and how write low/high works. It's difficult for me to explain so I'll try to use example...
by themrcul
Fri Aug 24, 2018 4:00 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Awesome, thanks Tiido. I think I'll purchase both and experiment when building the op-amp circuit. Can't wait to get started. Need to design the first PCB that holds most of the components together first though!
by themrcul
Thu Aug 23, 2018 10:44 am
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Hmmm. It's a shame the NJM2073 looks to be low sound quality.. I have found plenty of linear power regulators which take in up to 6V and spit out both 3.3V and 2.5V - so the mid-point voltage is easily solvable if necessary. In that case, which op-amp would you choose Tiido if you were me? Do you kn...
by themrcul
Tue Aug 21, 2018 11:13 pm
Forum: Megadrive/Genesis
Topic: Cart Design Questions
Replies: 40
Views: 4734

Re: Cart Design Questions

Thanks Tiido. I have done lots of learning since your last post. I know now that the LM358 for example will only output a puny amount of current, and not enough to surmount 75ohms on a model 1 MD, that is why the output goes through a power buffer circuit that you have designed there. In that case, ...