[TUHS] DEQNA / DELQA

[Folkert van Heusden via TUHS]

Hello,

Am currently working on emulating the DEQNA / DELQA Ethernet card in my 
70 emulator.

My sources of reference are:

* https://www.vaxhaven.com/images/5/50/EK-DEQNA-UG-001.pdf
* https://github.com/RetroBSD/2.11BSD/ for the (431 patchlevel) BSD 2.11 
sourceces

Am I right that  the DEQNA/DELQA keep scanning the ring-buffers by 
itself for packets to transmit?
* If so: wouldn't that slow down the whole system? (assuming a shared 
bus with the cpu) And how many times per second?
* If not: how does BSD (or whatever other OS runs on the PDP) notify the 
card that there is something queued? An LLM told me that for the DELQUA, 
there is a bit (12 I believe, that would be "QE_POWERUP 0x1000") in the 
CSR to tell the card to start transmitting, but I don't see that 
happening in the bsd driver code (it only detects if it s a DEQNA or 
DELQA card to print a message on the console, but nothing more).

Furthermore I use 
https://www.retro11.de/data/oc_w11/oskits/211bsd_rpethset.tgz from 
https://wfjm.github.io/home/w11/inst/systems.html#h_os_kits to test it. 
I changed the kernel to also support the deqna and when looking at my 
traces, I see that bsd sets the receive buffer addres and then polls CSR 
twice. Then nothing for a second or so and then the whole procedure of 
configuring the device happens again so it expects something to happen, 
but what? An interrupt?

regards

-- 
www.vanheusden.com [1]

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