On 2021-03-06 03:22, Eric Smith wrote:
On Fri, Mar 5, 2021 at 6:33 PM Paul Koning via cctalk
<cctalk@classiccmp.org <mailto:cctalk@classiccmp.org>> wrote:
I would have liked better comms. The USART has such a tiny FIFO
that you can't run it at higher than 9600 bps even with the J-11
CPU. At least not with RSTS; perhaps a lighter weight OS can do
better. The printer port is worse, that one can't run DDCMP
reliably at more than 4800 bps. I normally run DDCMP on the PC3XC,
which is a 4-line serial card that uses two dual UART chips (2681?)
with reasonable FIFO.
There seem to be a great many models of Unibus and Qbus multi-port async
serial boards, which present different register-level interfaces, e.g.
for Unibus, DH11, DHU11, DJ11, DM11, DZ11 . Which ones are considered
"best", for each bus, for use with a multitasking OS like RSTS/E or
RSX-11M+?
In general, you should pick a controller that can do as much as possible
with DMA.
Which means DH11 or DHU11 for Unibus.
Similar with Qbus: DHV11.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: b...@softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
