Issue
151 February 2003
Newcomer
Nitron
Motorola's
Leading 8/16-Pin MCUs
by
Jeff Bachiochi
Motorola’s
2003 design contest is upon us, so now’s the time
to get familiar with the Nitron family. This month,
Jeff introduces us to the flashy technology that
will soon permeate the low-end markets.
Start
•
The Core • Volatile
Memory
• OSC • MON
• Break
• Documentation
• Sources and PDF
It’s
no secret that engineers are embedding micros in
almost everything these days. I’ve been ranting
about small micros since Microchip introduced an
8-pin micro (circa 1997). Atmel hopped on the low
pin count bandwagon with the 8-pin AVR series. You
know this isn’t a pet rock fad when the company
that controls roughly 24% of the market for 8-bit
micros sets its sights on dominating every segment
of the microcontroller market. Motorola’s ammunition
comes in the form of a new flash memory product
line that’s based on the HC08. The company expects
its Nitron family of microcontrollers to have the
muscle and price that designers need to win design-ins.
The
kickoff begins with 8- and 16-pin packages using
0.5-µm, second-generation flash memory technology.
Currently, the Nitron family consists of three new
parts, each of which is available in an 8- (six
I/O) or 16-pin (14 I/O) package. Note that the base
parts have 1.5 KB of code space. The first option
adds a four-input, 8-bit ADC, and the second option
includes the ADC and increases the code space to
4 KB.
It’s
no secret. It’s no coincidence. Motorola’s vision
of dominance plays right into Motorola’s Flash Innovation
2003 design contest. If you’re unfamiliar with Motorola
micros or the 68HC08 architecture, this month’s
column will bring you up to speed. Soon, you’ll
be able to jump right in with the rest of us and
hopefully come up with a winning design.
If
you’re already familiar with the HC08, then skim
the features section for new information. As you
do, pay close attention to the description of the
free tools that Motorola has made available for
these parts.
THE
68HC908
The
Nitron family of 8-bit MCUs is a complex instruction
set computer (CISC) that uses von Neumann architecture
(i.e., data and code in one contiguous space). The core
CPU is the high-performance HC08, so the object code
is fully compatible with the other processors in the
family (see Figure 1).
|
(Click
here to enlarge)
|
Figure
1—The Motorola Nitron microcontroller family is
built around flash memory and the proven HC08 core
CPU. The on-board monitor (MON08) offers access
to the internals via half-duplex serial communications
on a single pin. |
In
addition to the flash memory, RAM, 16-bit timer, and
internal clock oscillator, there are several other important
features to consider: a watchdog, low-voltage detect/reset,
an embedded monitor, high-current I/O with interrupt
capability, and an optional ADC. Now, I’ll describe
the highlights of each feature.
