13 Apr
2005
13 Apr
'05
11:07 p.m.
On 4/13/05, Scott Stevens <chenmel at earthlink.net> wrote:
The 8530 is a useful part for dedicated purposes, but
isn't it severely
bandwidth cramped? I am thinking that it's the serial chip in the
Sparcstations, correct me if I'm wrong. A few years ago I was pondering
making a 'dialup connecting system with NAT server' out of a
SparcStation Classic (the little lunchbox type Sparc). I discovered
quickly that the serial ports on the Sparc are VERY speed constrained
because of the 8530 chip. It would have been impossible to connect my
USB Courier V-everything modem to it at, say 57,600 baud, because the
8530 just plain won't go that fast.
That's a SPARC design-dependent limitation... the same Z8530 is used
in the Macs as an AppleTalk/LocalTalk controller. We used the Z8530
in our Qbus and VAXBI COMBOARDs up to 128kbps (and no faster because
of external device compatibility, not any inherent speed limitations.
Limitations aside, unless you want to scope out T1 or fractional-T1
serial links, the chip is plenty fast enough. In my experience, a lot
of the links one wants to scope are between 110 bps and 56kbps,
anyway.
-ethan