64180 was availabe in that large pin dense dense dip or flatpack [J lead TQFP]
as is the Z180 and they are both about the same.? I have both and save for
clock speed same thing.? ITs biggest features are built in dual uart (dart similar),
a bit serial somewhat like I2C, timers and DMAC.? There are screamingly fast
versions to be found, I have a handful at 10mhz and one that is spec'ed for 20.
I also have SB180 that used the 64pin dip with the SCSI interface and the?
BCC180 (at 18.432mhz) using the TQFP as well as a few HB designs.
What makes the Z180/64180 less popular is programming the MMU is a
real pain.? The result of any programming is still only 64k addressable
space scattered in the 512K (64pin) or 1MB (TQFP) space.? That and
not everyone likes the onboard peripherals.
There is the much harder to find Z280, takes a z180 and adds 16bit wide (startup
configurable) bus for speed and extended but upward compatible instruction set
with indirect addressing modes and 24bit addressing via I&D spaces plus a real
MMU.? That part makes it easy to have 8mb ram and 8mb rom.? You need mask
level parts higher than H for fewest bugs.? Performance for the Jrev at 12mhz?
can beat a 8086 up to 16mhz.
However for just plain fun the base Z80 at 4-10mhz is a good pick for simple
systems.
Allison
