MAXQ3210-EJX MAXIM [Maxim Integrated Products], MAXQ3210-EJX Datasheet - Page 22

• Manufacturer Part Number: MAXQ3210-EJX
• Description: Microcontroller with Internal Voltage Regulator, Piezoelectric Horn Driver, and Comparator
• Manufacturer: MAXIM [Maxim Integrated Products]

Embedded debugging capability is available through
the JTAG-compatible Test Access Port. Embedded
debug hardware and embedded ROM firmware pro-
vide in-circuit debugging capability to the user applica-
tion, eliminating the need for an expensive in-circuit
emulator. Figure 5 shows a block diagram of the in-cir-
cuit debugger. The in-circuit debug features include:
• Hardware debug engine
• Set of registers able to set breakpoints on register,
• Set of debug service routines stored in the utility
The embedded hardware debug engine is an indepen-
dent hardware block in the microcontroller. The debug
engine can monitor internal activities and interact with
selected internal registers while the CPU is executing
user code. Collectively, the hardware and software fea-
tures allow two basic modes of in-circuit debugging:
• Background mode allows the host to configure and
• Debug mode allows the debug engine to take con-
Microcontroller with Internal Voltage Regulator,
Piezoelectric Horn Driver, and Comparator
22
Figure 5. In-Circuit Debugger
TMS
TDO
TCK
TDI
code, or data accesses
ROM
set up the in-circuit debugger while the CPU contin-
ues to execute the application software at full
speed. Debug mode can be invoked from back-
ground mode.
trol of the CPU, providing read/write access to inter-
nal registers and memory, and single-step trace
operation.
____________________________________________________________________
MAXQ3210
CONTROLLER
TAP
(UTILITY ROM)
ROUTINES
BREAKPOINT
In-Circuit Debug
SERVICE
ENGINE
DEBUG
DEBUG
CONTROL
ADDRESS
DATA
CPU
Careful PC board layout significantly minimizes crosstalk
among the reference input, comparator outputs, and dig-
ital inputs. Keep digital and analog lines separate, and
use ground traces as shields between them where pos-
sible. Separate CMPI and V
ning a ground trace between these pins. Bypass V
with a capacitor as low as 1µF and keep bypass capaci-
tor leads short for best noise rejection.
For general purposes, use a combination of a 10µF and
0.1µF capacitor on REGOUT. Note that the 0.1µF
capacitor is always required on REGOUT and must be
a good quality ceramic with low ESR. The internal regu-
lator is designed to be stable with an output filter
capacitor as low as 4.7µF and an ESR as high as 6Ω.
Larger REGOUT capacitor values and lower ESR pro-
vide better supply-noise rejection and transient
response. Note that some ceramic dielectric materials
(e.g., Z5U and Y5V) exhibit a large temperature coeffi-
cient for both capacitance and ESR, and a larger
REGOUT capacitance may be needed to ensure stabil-
ity at low temperatures.
The low-power, high-performance RISC architecture of
the MAXQ3210 makes it an excellent fit for many
portable or battery-powered applications that require
cost-effective computing. The analog comparator can
function as an A/D converter when simple analog mea-
surements are necessary, and the high-current I/O pin
can drive a power or status LED. Combined with the
high-output piezoelectric horn/transducer, the micro-
controller can function as both the “brain” and “mouth”
in a wide variety of monitoring applications.
The microcontroller includes an on-chip voltage regula-
tor that allows it to be powered directly off a 9V battery.
A low-battery detector allows the microcontroller to
monitor its own battery condition. The internal voltage
regulator can also drive external 5V circuitry while a 9V
battery drives the system.
This device can also be used as a low-cost analog-to-
digital converter (ADC). The single-slope conversion
method can be easily implemented using the internal
comparator and an internal timer. The basic implemen-
tation of such a converter is illustrated below. One of
the benefits of this approach is the small number of
Applications Information
Capacitor Selection and
Grounds and Bypassing
REF
Regulator Stability
from each other by run-
Applications
DD