exxos's Atari, Amiga & retro forum

Here they are.
Hopefully I haven't made too many mistakes.
The DB19 might be hard to find.

Also the 2nd ASCI port on there is not buffered... so I'll see about adding the required buffer to be on the safe side.

Edit : Added the buffers for the output port. Updated the file.

The schematic looks fine but i think you dont need the both 74ABT245.
Pin 96 has to be connected to ground using a resistor

Snipped from the manual:

If it is sensed low, the adapter is thought to be placed on an 8-bit slot where this pin is merely pulled low by the 27KW resistor. After having latched the input state, this pin is switched as the IOCS16B signal which is an open-drain output and is driven low during a 16-bit host data transfer. It is decoded from AEN and SA9-0

Then i would replace all logic IC against a GAL or a tiny CPLD like the Xilinx XC9536_44VQ and connect all signals to the CPLD Addresses and control signals from the st and from the Networkchip... then we can implement also interrupts. I think the driver isnt a problem because a interrupt driven driver does exisit.

the 245 are there to buffer the ASCI bus to the next device (taken from some atari doc), but I can remove them.
I'l fix pin 96, thanks for checking
I'm not against putting everything in a XC9536_44VQ (the XC9536XL-5VQG44C is less than $3 on Digikey).
I can make a second version with this (and add the required 3.3v LDO, but that easy to do).

Buffers removed. Pin 96 grounded via 1K, reduce board size. Routed TPIN and TPOUT differential pair.
So may be we should test this before replacing the logic with a XC9536XL ?

I use either OshPark here in USA. These would be about $65 for 3 boards and shipping is not bad. I also use PCBWay and shipping is about $21 to USA for a 5 or 10 boards pack. it would be $71 for 10 board (I changed the drill to 0.3mm to be in the cheap board tier).

Rodolphe

I was looking for sources for the RTL8019AS, not easy to find beside eBay and other Chinese sources. I also read horror stories about "fake" RTL8019AS .. so we might run into some issues if we can't find a proper source.
Another option is the Microchip LAN91C96, has a 8 bit mode and works in pretty much the same way as the RTL8019AS.
I wonder where Lotharek gets the RTL8019AS.
Rodolphe


Edit : looks like Future Electronic and Symmetry electronic have big quality in stock... so I guess we don't need to worry too much

Here in Germany I found quickly found the RTL8019AS to be available in at least two reputable online shops. I guess it's similar for Lotharek -- who is in Poland, afaik. However, given that it's a discontinued product, one will get sourcing issues sooner or later. If the LAN91C96 is software compatible and still in production, I'd go with that.

Good point. I also found the CS8900A is still available from Digikey and Mouser and is an ISA ethernet controller similar to the RTL8019AS

Edit : The key is to find a NE2000 compatible chip or the software will need to be rewritten.. The CS8900A datasheet doesn't explicitly say anything about NE2000 compatibility. Same thing for the 91C96.
This doesn't mean we can't build a new adapter with one of these but someone need to write the STinG driver and mintnet driver.

I was reading the "ARCHITEC.TXT" from the original etherne.zip file. So there is no interrupt.. but it says that it would be possible to use the parallel port interrupt for this. I might add a IRQ pin on the board for testing.

Same for a proper DMA mode, the doc says this should be possible for mintnet (and also Sting but would be more work) and send/read a full ethernet packet via DMA.
There are no DRQ and DACK pin on the RTL8019AS so not too sure how we could use the DMA mode. The RTL8019AS has "remote DMA" registers and can do DMA transfer over the 8bit interface.

Updated version of the board. Added a few things including a pin to wire to the parallel port interrupt (wire ton IRQ0 on the RTL8019AS and inverted using the remaining nor gate). Fixed some resistor and caps values. Should route without any issue in 8mil.
This version us fully routed in 8mil with 0.3mm drill so should be fairly cheap to make.
If someone could re-re-re-check the schematics
I can then order some PCB .


Rodolphe