maxq61hx-0000 Maxim Integrated Products, Inc., maxq61hx-0000 Datasheet - Page 16

• Manufacturer Part Number: maxq61hx-0000
• Description: 16-bit Microcontroller With Infrared Module
• Manufacturer: Maxim Integrated Products, Inc.

16-Bit Microcontroller with Infrared Module
The MAXQ61H provides port pins for general-purpose
I/Os that have the following features:
• CMOS output drivers
• Schmitt trigger inputs
• Optional weak pullup to V
While the microcontroller is in a reset state, all port pins
become high impedance with weak pullups disabled,
unless otherwise noted.
From a software perspective, each port appears as a
group of peripheral registers with unique addresses.
Special function pins can also be used as general-pur-
pose I/O pins when the special functions are disabled.
For a detailed description of the special functions avail-
able for each pin, refer to the part-specific user manual.
The MAXQ610 User’s Guide describes all special func-
tions available on the MAXQ61H.
An external quartz crystal or a ceramic resonator can
be connected between HFXIN and HFXOUT on the
MAXQ61H, as illustrated in Figure 7.
Noise at HFXIN and HFXOUT can adversely affect on-
chip clock timing. It is good design practice to place
the crystal and capacitors near the oscillator circuitry
and connect HFXIN and HFXOUT to ground with a
Figure 7. On-Chip Oscillator
16
mode
______________________________________________________________________________________
General-Purpose I/O
C1
On-Chip Oscillator
DD
C2
when operating in input
HFXIN
HFXOUT
V
DD
R
F
direct short trace. The typical values of external capaci-
tors vary with the type of crystal to be used and should
be initially selected based on the load capacitance as
suggested by the crystal manufacturer.
The lowest power mode of operation for the MAXQ61H
is stop mode. In this mode, CPU state and memories
are preserved, but the CPU is not actively running.
Wake-up sources include external I/O interrupts, the
power-fail warning interrupt, or a power-fail reset. Any
time the microcontroller is in a state where code does
not need to be executed, the user software can put the
MAXQ61H into stop mode. The nanopower ring oscilla-
tor is an internal ultra-low-power (400nA) 8kHz ring
oscillator that can be used to drive a wake-up timer that
exits stop mode. The wake-up timer is programmable
by software in steps of 125µs up to approximately 8s.
The power-fail monitor is always on during normal oper-
ation. However, it can be selectively disabled during
stop mode to minimize power consumption. This fea-
ture is enabled using the power-fail monitor disable
(PFD) bit in the PWCN register. The reset default state
for the PFD bit is 1, which disables the power-fail moni-
tor function during stop mode. If power-fail monitoring
is disabled (PFD = 1) during stop mode, the circuitry
responsible for generating a power-fail warning or reset
is shut down and neither condition is detected. Thus,
the V
RF = 1MΩ ±50%
C1 = C2 = 30pF
DD
< V
STOP
RST
MAXQ61H
condition does not invoke a reset state.
CLOCK CIRCUIT
Operating Modes