January
2006, Issue 186
Third-Generation
Rabbit
A
Look at the Rabbit 4000
You’ve
used Rabbit 2000 and 3000 microprocessors. Now it’s
time to get familiar with the Rabbit 4000, the newest
addition to the Rabbit line of low-EMI microprocessors.
According to Monte, the new design includes several
exciting features that will enable you to take your
communications, embedded control, and Ethernet connectivity
applications to the next level.
by
Monte Dalrymple
The
gestation period for new Rabbit Semiconductor microprocessors
seems to be about three years. I know this because I’ve
designed all three generations of Rabbit microprocessors.
Now it’s time to introduce you to the third-generation
device: the Rabbit 4000.
The
first two generations have been covered in past issues
of Circuit Cellar, so I won’t spend much time describing
the existing feature sets. Instead, I’ll concentrate
on the new expanded features. I’ll also describe some
of the thinking that went into the new design. Rabbit
has accumulated a lot of user feedback from the first
two generations, and I think it’s been put to good use.
One
thing that has helped in this regard has been the advance
of fabrication technology. We had a fixed transistor
budget when designing the Rabbit 2000. This led to a
number of compromises in functionality. Transistor budget
issues affected the Rabbit 3000 in a similar fashion.
Things
were different this time around. The expanded transistor
budget for the Rabbit 4000 provided room for a plethora
of new features. It also enabled us to address the compromises
left over from the previous generations.
