MAXIM MAXQ1740-DNS

ABRIDGED DATA SHEET
19-5893; Rev 0; 6/11
MAXQ1740
Magnetic Card Reader Security Microcontroller
General Description
Features
The MAXQ1740 is a low-power microcontroller that integrates a triple-track magnetic stripe reader interface, an
I2C interface, two SPIK interfaces, and one universal
synchronous/asynchronous receiver-transmitter (USART)
interface. Security features include an AES encryption
engine, a true hardware random-number generator, voltage-attack sensors, and a self-destruct input pin. A single-cycle 16-bit RISC MAXQM CPU powers the device. It
provides a high level of security for the magnetic stripe
reader by placing an ultra-secure microcontroller with
high-speed hardware encryption inside the magnetic
card reader head.
SCore Functionality
High-Performance, Low-Power, 16-Bit MAXQ20C
RISC Core
6MHz Internal Oscillator (±10%)
Up to 12MHz External Crystal Supported
1.7V to 3.6V Operating Voltage
1-Wire® Interface for Debugger and Flash
Programming
Optimized for C-Compiler
The device provides 16KB of flash memory, 1KB of fastwipe nonvolatile SRAM (NV SRAM), and 128 bytes of
data NV SRAM that instantaneously zeroizes its contents
when a tamper is detected. The 128 bytes can be used
as data RAM or working RAM for the AES. The fast-wipe
feature ensures that any data in the 1KB of memory is
destroyed before any application software can access it.
Factory programming of a unique 64-bit serial number,
and/or customer secret key(s), is available upon request.
The microcontroller runs within a wide 1.7V to 3.6V operating range. User-application firmware interfaces with the
triple-track magnetic stripe interface. Reference software
supports the reading of cards adhering to ISO 7811, ISO
7812, and ISO 7813. Source code to the reference software is available so applications can make adjustments
for custom card formats.
An ultra-low-power stop mode provides the ultimate in
low-power performance. In this mode, only a minimum
amount of circuitry is powered to support detection of
self-destruct events. When the main power supply is
present and the microcontroller is in stop mode, the
device has the option of exiting stop mode when stimulated by general-purpose port pins or the serial interfaces.
Applications
ATM/POS Terminals
Physical Security/Building Access
SSecurity
AES Hardware Accelerators
Hardware True Random-Number Generator
Self-Destruct Input for Tamper Detection
Permanent Loader Lockout Option
Code Scrambling
SMemory
16KB Flash Memory
512 Bytes Memory Page Sectors
1000 Erase/Write Cycles per Sector
1152 Bytes Fast-Wipe NV SRAM, 128 Bytes
Usable by Cryptographic Engine
6KB Utility ROM with User-Callable Routines
SI/O and Peripherals
Triple-Track Magnetic Stripe Head Interface
Two SPI Communication Ports
USART Communication Port
Two 16-Bit Timers
I2C Communication Port
Up to 16 General-Purpose I/O Pins
Up to 8 External Interrupt Pins
SLow Power Consumption
3µA Current in Lowest Power Stop Mode
3.75mA (typ) at 6MHz, 0.8mA (typ) at 1MHz
Divided System Clock Modes Available
SAdditional Peripherals
On-Chip Power-On/Power-Fail Reset
Supply Overvoltage Detection
Programmable Watchdog Timer
Wake-Up Timer
Ordering Information appears at end of data sheet.
SPI is a trademark of Motorola, Inc.
MAXQ and 1-Wire are registered trademarks of Maxim Integrated Products, Inc.
For related parts and recommended products to use with this part, refer to: www.maxim-ic.com/MAXQ1740.related
Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may
be simultaneously available through various sales channels. For information about device errata, go to: www.maxim-ic.com/errata.
����������������������������������������������������������������� Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
ABRIDGED DATA SHEET
MAXQ1740
Magnetic Card Reader Security Microcontroller
Block Diagram
WAKE-UP
TIMER
16KB FLASH MEMORY
16-BIT TIMER
1024B FAST-ERASE
DATA NV SRAM
16-BIT TIMER
256B FAST-WIPE
DATA/AES NV SRAM
SELFDESTRUCT
INPUT
USART
AES
ENCRYPTION
ENGINE
6KB UTILITY ROM
1-Wire
INTERFACE
MAXQ RISC
CPU
3-TRACK
MAG STRIPE
INTERFACE
WATCHDOG TIMER
INTERNAL
VOLTAGE
6MHz
MONITOR/
OSCILLATOR REGULATOR
RANDOMNUMBER
GENERATOR
MAXQ1740
I2C
SPI
SPI
GPIO
UP TO 16
GND +1.7V TO +3.6V
Detailed Description
Microprocessor
The MAXQ20C core supports the Harvard memory architecture with separate 16-bit program 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 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 contributes specific functions to the core. The
accumulator module consists of sixteen 16-bit registers
and is tightly coupled with the arithmetic logic unit (ALU).
Program flow is supported by a configurable soft stack.
Execution of instructions is triggered by data transfer
between functional register modules, or between a functional register module and memory. Since 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 maximum of flexibility and reusability that are important for a
microprocessor used in embedded applications.
The MAXQ1740 is a MAXQ20C-based microcontroller
intended for integration into magnetic card readers. It
can be interfaced directly to a 3-track magnetic card
reader head, allowing security features to be added to a
POS or ATM card reader right at the machine/card interface. Encryption is provided by a hardware AES engine.
Security features include a self-destruct input for tamper
detection, code scrambling, and fast-wiping of the NV
SRAM in the event of a tamper detection and supplyrail monitoring for overvoltage conditions. A 16KB flash
memory provides nonvolatile storage for user programs
and other static, nonvolatile data.
The MAXQ instruction set is highly orthogonal. All arithmetic and logical operations can use any register in
conjunction with the accumulator. Data movement is supported from any register to any other register. Memory
is accessed through specific data pointer registers with
auto increment/decrement support.
The device provides 1KB of fast-wipe NV SRAM and 128
bytes of data NV SRAM, which instantaneously zeroizes
its contents when a tamper is detected. The 128 byytes
can be used as data RAM or working RAM for the AES.
The fast-wipe feature ensures that any data in the 1KB of
memory is destroyed before any application software can
access it. Communication peripherals include a hardware I2C, a hardware USART, and two hardware SPIs.
A 1-Wire port is available for system programming and
application debugging.
• 128 bytes of instantaneous zeroization NV SRAM
Memory
The microcontroller incorporates several memory types:
• 16KB flash memory
• 1152 bytes fast-wipe NV SRAM
• 6KB utility ROM
• RAM-based software stack
The NV SRAM is cleared by a DRS event. The 128-byte
memory can be used as general-purpose memory if
the AES function is not in use. Starting the AES engine
invalidates data stored in this memory. See Figure 5 for
the memory map.
���������������������������������������������������������������� Maxim Integrated Products 11
ABRIDGED DATA SHEET
MAXQ1740
Magnetic Card Reader Security Microcontroller
Applications Information
Additional Documentation
The low-power, high-performance RISC architecture of
this device makes it an excellent fit for many portable or
battery-powered applications requiring security.
Designers must have the following documents to fully use
all the features of this device. This data sheet contains
pin descriptions, feature overviews, and electrical specifications. Errata sheets contain deviations from published
specifications. The user’s guides offer detailed information about device features and operation.
Grounds and Bypassing
Careful PCB layout significantly minimizes system-level
digital noise that could interact with the microcontroller or
peripheral components. The use of multilayer 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 rejection and place the capacitors as close as possible to the leads of the device.
CMOS design guidelines for any semiconductor require
that no pin be taken above VDD or below GND. Violation
of this guideline can result in a hard failure (damage to
the silicon inside the device) or a soft failure (unintentional
modification of memory contents). Voltage spikes above
or below the device’s absolute maximum ratings can
potentially cause a catastrophic latchup of the device.
Microcontrollers commonly experience negative voltage spikes through either their power pins or generalpurpose 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.
• This MAXQ1740 data sheet, which contains electrical/
timing specifications and pin descriptions.
• The revision-specific MAXQ1740 errata sheet.
• The MAXQ1740 User’s Guide, which contains detailed
information on core features and operation, including
programming.
Development and
Technical Support
A variety of highly versatile, affordably-priced development tools for this microcontroller are available from
Maxim and third-party suppliers, including:
• Compilers
• In-circuit emulators
• Integrated development environments (IDEs)
A partial list of development tool vendors can be found at
www.maxim-ic.com/MAXQ_tools.
For technical support, go to https://support.maxim-ic.
com/micro.
Ordering Information
TEMP RANGE
OPERATING
VOLTAGE (V)
FLASH MEMORY
(KB)
DATA MEMORY
(KB)
MAXQ1740-FBX+
0NC to +70NC
1.70 to 3.6
16
1
28 TQFN-EP*
MAXQ1740-DNS+
0NC to +70NC
1.70 to 3.6
16
1
Bare die
PART
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
PIN-PACKAGE
Package Information
For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or
“-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains
to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
OUTLINE NO.
LAND PATTERN NO.
28 TQFN-EP
T2844+1
21-0139
90-0035
Note to readers: This document is an abridged version of the full data sheet. To request the full data sheet, go to
www.maxim-ic.com/MAXQ1740 and click on Request Full Data Sheet.
���������������������������������������������������������������� Maxim Integrated Products 22