Does the Hydra A500 Amiganet Ethernet adapter use DMA?

[cpfuture]

Hi,

I bought an Amiganet Hydra 500 Ethernet interface for my A500:

Link

I know the A2000 version of the Hydra uses DMA, but there are some indications I found whilst Googling that the A500 version does not. Can anyone confirm this?

I have an A500+ with a Viper 520 inside. The Viper 520 documentation states that sidecar expansions that use DMA (like the A570 and A590) will not work when the Viper is installed. So, it would actually be a good thing if the A500 Hydra didn't use DMA.

The Hydra is still underway, so I haven't been able to just test it out myself. If it doesn't work with the Viper I still have loads of A500's left that will work with the Hydra :-) Just wondering if anyone here knows for sure so I don't get my hopes up too much.

[Piru]

Comparing AmigaNet Hydra 500 and AmigaNet ZorroII, they seem to be the exactly same card, with the A500 model having Z2-to-500-expansion-slot adapter (it even reads "AMIGANET A500 CONNECTOR"). Makes sense, since it allowed reusing the design and components.

Whether it uses DMA or not, I have no clue, but I can't see why it couldn't. A500 expansion port is basically Z2 slot, and as far as I know it is cabable of DMA.

Compare:
AmigaNet  Zorro II card
AmigaNet Hydra A500 insides

[cpfuture]

Makes sense, Piru. Thanks.

I'll update this thread with the outcome when the Hydra arrives, in case anyone else happens to be Googling for the same thing.

[cpfuture]

I promised to update this thread when I got the Amiganet unit. Well, it arrived in the mail today! Unfortunately the A500 version does not have the AUI 15 pin D-connector that the stand alone Zorro II card has. It only has 2 BNC connectors.... So ATM I don't have the means to test the Amiganet device 100%.

I quickly hooked it up to my A500 and installed the SANA-II compatible hydra.device driver. I'm using AmiTCP 3.0b2 and I configured the card in AmiTCP:db/interfaces, assigned it an IP address with ifconfig. Now, when I ping the card's IP I get a response! When I run Showconfig I also see the board reported as 2121/1 which is the correct Autoconfig ID according to amiga.resource.cx.

BNC-RJ45 solutions are quite a bit more expensive than a simple AUI D15-RJ45 converter. I am currently on the look out for an old cheap 10Mb hub that has both BNC and RJ45 ports so I can connect the Hydra to a free Ethernet port on my iMac.

The reason I wondered about the DMA issue is that the Viper 520 manual states that A500 side car devices that employ DMA don't work together with the Viper.  But given the fact that the card is detected and pingable, I assume this means the device is in good shape and works with my Viper 520, which is all I needed to know ! :-) (or am I being too optimistic).

I found this old Usenet discussion that seems to indicate a non-DMA Amiganet version was planned for the A500:

Link

Also a promotional flyer for the GVP A-Net 500 Ethernet adapter (a rebadged version of the Hydra) seems to indicate the same:

* All controllers have 16kB of onboard static RAM allowing DMA directly to/from the network. A2000 controller also has DMA sequencer allowing DMA transfers directly from/to the Amiga's memory.

I guess that could be interpreted as the A500 version having no DMA? Whatever the case, I hope to be able to hook the Hydra up to my iMac soon


 :-D

[cpfuture]

BTW, anyone interested in seeing photos from my Viper 520 and Hydra Amiganet 500 adapter can see them here:

(Uploads to A.org don't seem to be working for me.... :-( )

Hydra Amiganet 500
Hydra Amiganet 500
Hydra Amiganet 500
Viper 520
Viper 520

Yes, I'm very happy with these rare devices  :-D

[Zac67]

I don't think any Amiga NIC uses DMA - it'd take a lot more logic to accomplish than is visible on the card and noboby had the performance needs back in those days. There were very few ISA NICs with DMA, the only one I remember was an SMC (EtherPlus?). 3C509, NE2000 were PIO mode only. The 3Com cards used a clever buffer design that actually had the same performance as SMC for half the price.