19 Feb
2010
19 Feb
'10
4:18 p.m.
On 2/19/10, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I've done both. I've personally never had mechanical stability
problems with protoboards, but then I don't tend to wedge in 0.1"
header pins into my boards. I insert ICs, 1/4W resistors, various
capacitors, wires, crystals, LEDs and such, but rarely do I insert
header pins. I've always felt that they were "too large", even though
I know lots of people stuff them in there all the time.
Indeed. Quite distinctive.
I have read about the 68012, but don't think I've seen one in the wild.
It does. The difference isn't onerous - at least starting with
AmigaDOS 1.2 if not 1.1 (not sure about 1.0), you could upgrade your
68000 to a 68010 for an approximate 5% effective speed "boost" - this
was entirely due to the one-instruction DBcc "loop-mode cache" in
random places in the OS and in applications. As long as your
applications didn't try to execute any "MOVE from SR" instructions
(http://www.cpu-world.com/CPUs/68010/), no changes were required. If
you _did_ have some apps that did that, there a trap handler for that
on, IIRC, an early Fish disk. It would catch the privilege exception,
grab the status/condition code value and return the value to the
trapping instruction.
One app that was used to tell if you had the patch applied was the
AmigaDOS 1.1 calculator. With AmigaDOS 1.2, the app made an OS call
to get the required value. The older app used a "forbidden
instruction" so it made a good test.
If you are rolling your own OS or writing embedded code, it's not
really that hard to determine what size of stack frame you'll have and
handle both. I was responsible for replacing 68000s with 68010s in
the final COMBOARD product (partially to take advantage of "loop mode"
when dumping buffers across the DMA interface, increasing the block
speed of the board with a $50 chip). I don't think the code changes
relating to the 68010 took me more than part of an afternoon to
implement.
It's good to remember that it's so, but rather easy to accomplish once
you are that deep in the code.
-ethan
Yes, I have
been using breadboards for more than 20 years and never
had a problem with them. Sure, you must not try to stick thick wires
I must have been unlucky. I tried several of them in my younger days
(Eurobreadboars, the CSC/GSC Protoboards, etc) and had no end of
problems. In the end I started just soldering upo the circuits on
stripboard, and my desigens started working first time. [1] The local pound shop (a similar concept to dollar
stores) was selling
a camping lamp with 24 white LEDs for a pound.
I'd buy that for a pound! (and repurpose it, as you have).
BTW, the
article says it is an MC68008, so you did not need to count
24 pins (on one side) :-)
Oh, I didn't . I noticed it was a 0.6" wide package. The 68000 and 68010
DIL packages are 0.9" wide. The 68010 is
pin compatible to the 68000, but if you are in OS stuff,
Indeed. There is also a PGA version of the 68010, which is used in some
HP machines IIRC there's a 68012 which had more addres mins bought out,
but otherwise had the same PGA pinout you have to
modify some software if you are handling stack frames.
Those are not identical on the 68000 and 68010.
IIRC, the 68010 pushes more onto the stack on an interrupt.