27C400/27C800 EPROM emulator

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PaulJ_2.0
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Re: 27C400/27C800 EPROM emulator

Post by PaulJ_2.0 » Mon Jul 15, 2019 2:27 pm

terriblefire wrote:
Mon Jul 15, 2019 11:42 am
If its USB programmed its perfect for me. No more unplugging.
Yeah this would be great, I concur.

guus.assmann
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Location: Ede Netherlands

27C400/27C800 EPROM emulator

Post by guus.assmann » Mon Jul 15, 2019 6:35 pm

Looks like a nice product and it's up to modern standards / sizes.
I'm very much interested in testing it.
What would be the cost and what parts are used?
I may have quite a bit of the parts in stock and do have soldering skills.

Keep up the good work please ! :D

terriblefire
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Re: 27C400/27C800 EPROM emulator

Post by terriblefire » Mon Jul 15, 2019 7:14 pm

This is an amazing product. I shall rave about them on a stream!!!
———
I get cranky when asked to repeat myself.

chucky
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Re: 27C400/27C800 EPROM emulator

Post by chucky » Mon Jul 15, 2019 11:16 pm

cmorley wrote:
Mon Jul 15, 2019 9:30 am
terriblefire wrote:
Mon Jul 15, 2019 8:02 am
Can it be wiped/reprogrammed by a TL866?
No, only USB program via a virtual comm port - just fire a BIN file over serial. I don't think the 74LVC buffer on A9 or _BYTE/Vpp would survive the ID read/Vpp voltage :shock: (I was going to add a warning "do not insert in a EPROM programmer" rather than add protection on those pins)
chucky wrote:
Mon Jul 15, 2019 8:11 am
USB programmed? so I could program it while still on the board? this would help me alot when developing DiagROM and I need to test on a real machine.. *starts thowing money on monitor*
Yes fully in circuit programmable. The data bus goes high-Z when you program so maybe turn the Amiga power off though!
Damn this is now on my "MUST HAVE" list :)

cmorley
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Joined: Tue May 28, 2019 5:46 pm

Re: 27C400/27C800 EPROM emulator

Post by cmorley » Tue Jul 16, 2019 6:57 am

guus.assmann wrote:
Mon Jul 15, 2019 6:35 pm
Looks like a nice product and it's up to modern standards / sizes.
I'm very much interested in testing it.
What would be the cost and what parts are used?
I may have quite a bit of the parts in stock and do have soldering skills.

Keep up the good work please ! :D
What machine would you test with? Cost - not sure yet it all depends on quantity. They will not be expensive - I am in the fair price for fair kit camp.

I think if TerribleFire and Chucky test then the Amigas are covered. I have an Acorn Master user lined up (will do an 16->8 bit adapter PCB for that). An Atari guru would be good (ST needs adapters I think). I will try it in my Acorn A3000 (again adapter :|). I will probably draw (but not immediately) a C64 kernal ROM adapter and a Megadrive cart adapter.

Anyone developing ST ROM software? (OS or diagnostics like Chucky with diagrom?)

What other machines do people OS switch on a regularly?

Some non-computer hardware would be good - synths & drum machines for example... easy way to change patches without swapping ROMs. Anyone into this?

I will create a library of adapters and instructions for different hardware. All adapters will be open source with gerbil files - I might do an affiliate link with PCBWay (or similar) to simplify ordering.

Chris

guus.assmann
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Location: Ede Netherlands

27C400/27C800 EPROM emulator

Post by guus.assmann » Tue Jul 16, 2019 8:03 am

Hello,

As I'm the proud owner of quite some machines, I would be able to test some.
I've got 8-bit Atari machines. Those would need an adapter, but that's not very difficult. (800XL and 130XE)
And I have Mega ST boards. These are 68000 units.
Maybe a TT would do? Although that contains 4 Roms. 68030 based.
But just replacing 2 Rom's is possible of course.
In that case, it would be very nice if loading the content is possible per emulated Eprom. (2 times 8 Bit seperately)
But using the help programs for an Eprom programmer, it's not difficult to combine binaries the right way.

BR/
Guus

Cyprian
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Re: 27C400/27C800 EPROM emulator

Post by Cyprian » Tue Jul 16, 2019 10:16 am

cmorley wrote:
Tue Jul 16, 2019 6:57 am
Anyone developing ST ROM software? (OS or diagnostics like Chucky with diagrom?)

What other machines do people OS switch on a regularly?
In case of Atari ST/TT/Falcon, we use ROMs with different OSes like: EmuTOS which is still developed, TOS (most popular are: 4.04/2.06/1.04) and MagiC.
Lynx II / Jaugar / TT030 / Mega STe / 800 XL / 1040 STe / Falcon030 / 65 XE / 520 STm / SM124 / SC1435
SDrive / PAK68/3 / Lynx Multi Card / LDW Super 2000 / XCA12 / SkunkBoard / CosmosEx / SatanDisk / UltraSatan / USB Floppy Drive Emulator / Eiffel / SIO2PC / Crazy Dots / PAM Net
Hatari / Steem SSE / Aranym / Saint
http://260ste.appspot.com/

cmorley
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Re: 27C400/27C800 EPROM emulator

Post by cmorley » Fri Aug 02, 2019 5:58 pm

Right so after a couple weeks of inactivity I'll get on with porting the firmware from my dev board to this prototype this weekend & do some basic tests to check they actually work and there is nothing wrong with the PCBs or schematic.

I'll then solder a few up and post them out to those who voulenteered to do some testing.

Guus - for the STs are you willing to make adapter PCBs?

I realised a few days ago that because the FLASH is so fast and most of the retro computers are slow an adapter on a 32 bit machine with some logic and a couple of 74 series latches you could use one board and double read (hook A0 to a clock & latches clock to same line). So you wouldn't actually need 2 for an Amiga 1200 or Acorn A3000 etc... potentially.

cmorley
Posts: 19
Joined: Tue May 28, 2019 5:46 pm

Re: 27C400/27C800 EPROM emulator

Post by cmorley » Tue Aug 06, 2019 1:10 pm

Update:

Firmware ported from the dev board to the prototype. Pinouts changed on the CPLD and STM32 and I altered the signal routing through the CPLD but so far so good. It's in an A500 now with 3.1.4, DiagROM, 3.1 and 1.3 programmed in & ROM switching works. Currently has the SWDIO header soldered on for dev - those pads are used for the active low ROM switching (~RESET or button etc) and optional LED output/spare pin. Otherwise firmware is by DFU over the USB.

Programs 512KB ROM in about 20s at the moment. I can't make it go faster because I've run out of space in the CPLD and there is no point adding cost for a bigger CPLD. It might be possible to play tricks using the built in CPLD FLASH - but there is no point. I think 20s to program is fine.

I still have some more Firmware work to do - implement the STM32 option bytes to retain pull up/down/romsize etc (all 2 bytes woooo!) and put an option to erase the first sector of the STM FLASH so it will go to DFU mode next boot (reset to the boot loader is not supported on an 32F0xx - erase is the official method).

I will assemble some more boards this week. Might well be able to get them in the post before the weekend...

In an machine with SWD cable on:
Photo0627_800.jpg
Photo0627_800.jpg (130.85 KiB) Viewed 1516 times
The original dev board for the curious:
Photo0634_800.jpg
Photo0634_800.jpg (89.42 KiB) Viewed 1516 times

cmorley
Posts: 19
Joined: Tue May 28, 2019 5:46 pm

Re: 27C400/27C800 EPROM emulator

Post by cmorley » Sun Aug 11, 2019 7:00 pm

Ha. Typical...

I'm building up the balance of the 10x PCBs I got for these prototypes and I have run out of 100nF 0402 caps! I'll put a Mouser order in tomorrow.

So looking like posting out back end of next week. I'll PM people to arrange the details with them.

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