MAXQ618
16-Bit Microcontroller with Infrared Module
11
Maxim Integrated
Pin Description (continued)
Detailed Description
The MAXQ618 provides integrated, low-cost solutions
that simplify the design of IR communications equipment
such as universal remote controls. Standard features
include the highly optimized, single-cycle, MAXQ, 16-bit
RISC core; 80KB flash memory; 2KB data RAM; soft
stack; 16 general-purpose registers; and three data
pointers. The MAXQ core has the industry’s best MIPS/
mA rating, allowing developers to achieve the same per-
formance as competing microcontrollers at substantially
lower clock rates. Lower active-mode current combined
with the even lower MAXQ618 stop-mode current (0.2FA
typ) results in increased battery life. Application-specific
peripherals include flexible timers for generating IR car-
rier frequencies and modulation. A high-current IR drive
pin capable of sinking up to 25mA current and output
pins capable of sinking up to 5mA are ideal for IR appli-
cations. It also includes general-purpose I/O pins ideal
for keypad matrix input, and a power-fail-detection circuit
to notify the application when the supply voltage is near-
ing the microcontroller’s minimum operating voltage.
At the heart of the device is the MAXQ 16-bit, RISC core.
Operating from DC to 12MHz, almost all instructions exe-
cute in a single clock cycle (83.3ns at 12MHz), enabling
nearly 12MIPS true-code operation. When active device
operation is not required, an ultra-low-power stop mode
can be invoked from software, resulting in quiescent
current consumption of less than 0.2FA (typ) and 2.0FA
(max). The combination of high-performance instructions
and ultra-low stop-mode current increases battery life
over competing microcontrollers. An integrated POR cir-
cuit with brownout support resets the device to a known
condition following a power-up cycle or brownout condi-
tion. Additionally, a power-fail warning flag is set, and a
power-fail interrupt can be generated when the system
voltage falls below the power-fail warning voltage, VPFW.
The power-fail warning feature allows the application to
notify the user that the system supply is low and appro-
priate action should be taken.
Microprocessor
The device is based on Maxim’s low-power, 16-bit
MAXQ20S family of RISC cores. The core supports the
Harvard memory architecture with separate 16-bit pro-
gram and data address buses. A fixed 16-bit instruction
word is standard, but data can be arranged in 8 or 16
bits. The MAXQ core in the device is implemented as
a pipelined processor with performance approaching
1MIPS per MHz. The 16-bit data path is implemented
around register modules, and each register module con-
tributes specific functions to the core. The accumulator
module consists of sixteen 16-bit registers and is tightly
coupled with the arithmetic logic unit (ALU). A configu-
rable soft stack supports program flow.
Execution of instructions is triggered by data trans-
fer between functional register modules or between a
functional register module and memory. Because data
movement involves only source and destination modules,
circuit switching activities are limited to active modules
only. For power-conscious applications, this approach
localizes power dissipation and minimizes switching
noise. The modular architecture also provides a maxi-
mum of flexibility and reusability that are important for a
microprocessor used in embedded applications.
The MAXQ instruction set is highly orthogonal. All arith-
metical and logical operations can use any register in
conjunction with the accumulator. Data movement is sup-
ported from any register to any other register. Memory
is accessed through specific data-pointer registers with
autoincrement/decrement support.
PIN
NAME
FUNCTION
BARE DIE
TQFN-EP
NO CONNECTION PINS
32, 34, 37
—
DNC
Do Not Connect. Do not bond out for normal operation.
—
26, 27
N.C.
No Connection. Not internally connected.
EXPOSED PAD
—
EP
Exposed Pad. For low-current applications (< 10mA of GPIO current, exclusive of IRTX
sink current), these pins can be left unconnected. If used, they should be connected
directly to the ground plane.