kodak80 blog

[Badwolf]

As shared on other forums. My ISA Cartridge adapter works fine with bodge wires from underneath the GLUE IC (pins 17 & 18) for ROM3 & ROM4.

Looks good!

What address lines are exposed on the ISA slot? No chance of doign the ROM3/4 decode yourself?

Cheers,

BW

[kodak80]

As shared on other forums. My ISA Cartridge adapter works fine with bodge wires from underneath the GLUE IC (pins 17 & 18) for ROM3 & ROM4.

Looks good!

What address lines are exposed on the ISA slot? No chance of doing the ROM3/4 decode yourself?

Cheers,

BW

The required address lines for the decode are not on the ISA slot. They are on the GAL IC that is used for the STGA1040 logic.

Here is the ISA slot schematic:

ISA pinout.png

I believe this is the decode required for ROM3/ROM4:

Code: Select all

/ROM3 := /AS & A23 & A22 & A21 & A20 & A19 & /A18 & A17 &  A16 & RW
/ROM4 := /AS & A23 & A22 & A21 & A20 & A19 & /A18 & A17 & /A16 & RW;

[Badwolf]

The required address lines for the decode are not on the ISA slot. They are on the GAL IC that is used for the STGA1040 logic.
...
I believe this is the decode required for ROM3/ROM4:

Code: Select all

/ROM3 := /AS & A23 & A22 & A21 & A20 & A19 & /A18 & A17 &  A16 & RW
/ROM4 := /AS & A23 & A22 & A21 & A20 & A19 & /A18 & A17 & /A16 & RW;

Yeah, that looks right.

What a shame! All those pins and it stops at A18.

BW

[kodak80]

I tested the v1.1 of my ISA cart adapter yesterday and it works which is great considering I had to move from Eagle to KiCad for v1.1 due to the size of the PCB. It was too big when I moved the cartridge port outside the ATX casing and Eagle (free version) would not allow the size board needed.

I have spent time today working on the next version (v1.2) of the ISA cartridge adapter and have added in:

• a 40 pin internal header to allow an EtherNEC adapter to be connected using a 40 pin IDC ribbon cable

• Forget-Me-Clock II components to allow a real-time clock

Cart Adapter RTC 40 pin Header-front.png

Whilst I was working on this, I also deciphered the EtherNEC adapter information to create the 8-bit ISA board to connect up to the above new cartridge 40 pin header which should allow network connectivity to the mATX Atari ST.

EtherNEC2022-front.png

And I have also created a fix adapter for the ACSI header that should work

ATX ACSI 20 pin Header Fix-top.png

ATX ACSI 20 pin Header Fix-bottom.png

I have placed an order for these PCBs and will get them tested once they arrive.

[HigashiJun]

Looks good !

[kodak80]

Version 1.2 is now tested and RTC, cartridge port and internal 40 pin header work. EtherNEC is now also tested and works when connected to the cartridge adapter internal header.

EtherNEC testing (1).jpg

EtherNEC testing (2).jpg

EtherNEC testing (3).jpg

EtherNEC testing (4).jpg

EtherNEC testing (5).jpg

EtherNEC testing (6).jpg

Gerbers for the Cartridge Adapter and EtherNEC boards are now available on the mATX page on my website:
https://chillichai.com/atari-st-micro-atx/

[PhilC]

Thanks for sharing @kodak80

[DoG]

Nice. Thx.

I found some DIY NE2000 card on github, based on the Realtek chip, that I will try and build. Hopefully compatible with the EtherNEC and cheaper then the NE2000 on eBay. I found both 8-bit and 16-bit ISA card. I guess the 8-bit will be enough since it is only a 8-bit ISA Socket used on the EtherNEC adapter?

[kodak80]

Yes, 8 bit ISA slot is what is in the EtherNEC adapter.

I have built up 3 x 8 bit network cards from this one: https://github.com/skiselev/isa8_eth

I need to find a way to program the 93C46 - 1 Kbit EEPROM as the network cards do not seem to work without the chip being programmed. A program is provided to do this but I don't have a working PC with an ISA slot at the moment.

[DoG]

Exactly the one I was thinking of. :D