MAXQ2010
16-Bit Mixed-Signal Microcontroller
with LCD Interface
30
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Applications Information
The low-power, high-performance RISC architecture of
this device makes it an excellent fit for many portable or
battery-powered applications that require cost-effective
computing. The high-throughput core is complemented
by a 16-bit hardware multiplier-accumulator, allowing
the implementation of sophisticated computational
algorithms. Applications benefit from a wide range of
peripheral interfaces, allowing the microcontroller to
communicate with many external devices. With integrat-
ed LCD support of up to 160 segments, applications
can support complex user interfaces. Displays are dri-
ven directly with no additional external hardware
required. Contrast can be adjusted using a built-in,
adjustable resistor. The simplified architecture reduces
component count and board space, critical factors in
the design of portable systems.
The MAXQ2010 is ideally suited for applications such
as medical instrumentation, portable blood-glucose
equipment, and data-collection devices. For blood-glu-
cose measurement, the microcontroller integrates an
SPI interface that directly connects with analog front-
ends for measuring test strips.
Grounds and Bypassing
Careful PCB layout significantly minimizes noise on the
analog inputs, resulting in less noise on the digital I/O
that could cause improper operation. The use of multi-
layer boards is essential to allow the use of dedicated
power planes. The area under any digital components
should be a continuous ground plane if possible. Keep
any bypass capacitor leads short for best noise rejec-
tion and place the capacitors as close to the leads of
the devices as possible.
Separate ground areas must be provided for the analog
(AGND) and digital (DGND) portions, connected
together at a single point.
CMOS design guidelines for any semiconductor require
that no pin be taken above VDVDD or below DGND.
Violation of this guideline can result in a hard failure
(damage to the silicon inside the device) or a soft fail-
ure (unintentional modification of memory contents).
Voltage spikes above or below the device’s absolute
maximum ratings can potentially cause a devastating
IC latchup.
Microcontrollers commonly experience negative volt-
age spikes through either their power pins or general-
purpose I/O pins. Negative voltage spikes on power
pins are especially problematic as they directly couple
to the internal power buses. Devices such as keypads
can conduct electrostatic discharges directly into the
microcontroller and seriously damage the device.
System designers must protect components against
these transients that can corrupt system memory.
TAP
CONTROLLER
CPU
DEBUG
ENGINE
DEBUG
SERVICE
ROUTINES
(UTILITY ROM)
CONTROL
BREAKPOINT
ADDRESS
DATA
TMS
TCK
TDI
TDO
MAXQ2010
Figure 9. In-Circuit Debugger