[EFI68k] new release and group survey

[Michael F. Sargent]

> I believe I measured less than 100uA at room temp.

Well that certainly won't be a problem!

With that sort of low power consumption, you could get away with just using
a super-cap. They are available from 1 to 5 Farads (not uF). That is exactly
the job they were designed for. Put in an isolating diode (low leakage),
and just connect that to +5. As soon as power is supplied, the super-cap
will be charged, and at 100 uA it will take weeks (if not months) to discharge.
This also offers wonderful protection against low voltage when the starter is
grinding. All in all, this is probably a much better bet than a battery.

> (256*1024)/(9600/10)/60=4.5 minutes (binary transfer) ???

All right, I was just figuring in my head!

I will probably be running from a laptop PC, so I can probably get 115K baud
so that would take around 23 seconds to download 256 KB. I would probably
burn a PROM monitor, the C RTL, and RTEMS into a ROM so that they would not
need to be reloaded. If the EFI code is (say) 64K, then the download time
would only be about 6 seconds. That's no problem. No need for a parallel
connection.

Architecturally, I would probably build the EFI code to use a set of jump
tables to call major functions. On startup, the jump tables would be copied
to RAM. A baseline build could be burnt into EPROM. Part of the normal
operation of the EFI code (background task) would look for communication with
a host and allow code/data to be downloaded. If a new function is downloaded,
then only the address in the jump table needs to be updated and the new
function in RAM will be called rather than the old code in EPROM.

Primarily this is done to avoid having to blow PROMs too often. With battery
backup of the SRAM, the patch code/table doesn't even need to be reloaded
unless needed.

All in all, this is starting to sound very nice!
                                                Mike
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| Michael F. Sargent   | Net: msargent at gallium.com | Phone: 1(613)721-0902 |
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