5 Mar
2021
5 Mar
'21
7:26 p.m.
On Fri, Mar 5, 2021 at 7:05 PM Chris Zach via cctalk
<cctalk at classiccmp.org> wrote:
And then isn't the M3107 DHQ11 slightly better than the M3104 DHV11?
DHQ11 User Guide, EK-DHQ11-UG-002
The main application of the DHQ11 is for interactive terminal
handling; it can also be used for data concentration and real-time
processing. It has two programming modes, DHV11 and DHU11. The
register sets in these modes are compatible with those of the DHV11
and DHU11 respectively. The preferred mode of operation is DHU11 mode.
The main features of the DHQ11 are:
For transmission: DMA transfers; or for each line, program transfers
to a 1-character transmit buffer in DHV11 mode, or to a 64-character
transmit FIFO in DHU11 mode.
For receive: a 256-entry FIFO buffer for received characters, dataset
status changes, and diagnostic information.
(And also, the M3118 CXA16 and M3119 CXY08 are essentially equivalent
to the M3107 DHQ11 from a software and performance point of view, but
in S-handle card form factor?)
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+?
DHV11 is what you need for a lot of users: Bigger FIFO buffer for input,
DMA access to do a lot of characters in a few bus cycles, and oddly
enough intelligence to do things like automatically send XON and XOFF
without having to bother the CPU. Apparently you can send and receive on
all 8 channels at 9600 baud simultaneously which is pretty good.