ST ST32F256 User Manual

Smartcard MCU with 32-bit ARM Cortex™ M3 CPU

259a.ai

Micromodule Wafer

and 256 Kbytes high density Flash memory

Features

Hardware features

■ ARM Cortex™-M3 32-bit RISC core

■ 8 Kbytes of user RAM

■ 256 Kbytes of user Flash memory with OTP

area:
– 10-year data retention
– 100,000 Erase/Write cycles per page
– Page granularity of 128 Bytes
– Block granularity: 1 Kbyte
– 128 Bytes of OTP for User
– Page Erase time 3 ms
– Block Erase 1 Kbyte in 15 ms
– Programming performance up to 10µs/byte
– Flash Erase / Write Protection software

programmable on 64 Kbyte sectors

■ Asynchronous Receiver Transmitter

supporting ISO 7816-3 T=0 and T=1 protocols

■ Two 16-bit timers with interrupt capability

■ 1.8V, 3V and 5V supply voltage ranges

■ External clock frequency from 1 up to 7.5 MHz

■ High performance provided by:

– CPU clock frequency up to 20 MHz
– External clock multiplier (2x, 3x, and 4x)

■ Current consumption compatible with GSM

and ETSI specifications

■ Power-saving Standby state

■ Contact assignment compatible ISO 7816-2

■ ESD protection greater than 4 kV (HBM)

ST32F256

Data brief

Security features

■ Monitoring of environmental parameters

■ Protection against faults

■ ISO 3309 CRC calculation block

■ True random number generator

■ Unique serial number on each die

■ Hardware DES accelerator

Software features

■ Flash Loader

■ Flash drivers

Development environment

Software development and firmware generation
are supported by a comprehensive set of
development tools dedicated to software design
and validation:

■ C Compiler

■ Simulator

■ Emulator

Applications

ST32F256 major applications include:

September 2009 Doc ID 15925 Rev 1 1/4

For further information contact your local STMicroelectronics sales office.

■ Mobile communications (GSM, 3G and CDMA)

■ Java Card™ applications

www.st.com

1

Description ST32F256

Ai12577

Internal Bus

I/O

IART

GND

Cortex™

M3
CPU
Core

2 x

16-bit

Timers

CRC

Module

CLK

Clock

Gene-

rator

Module

Vcc

Tr u e

Random

Number

Gene-

rator

RAM

ST ROM

Security

Adminis-

trator

RESET

Flash

memory

DES

Accelerator

ST ROM

Firewall

1 Description

1.1 Hardware description

The ST32F256 is a serial access microcontroller designed for secure mobile applications
that incorporates the most recent generation of ARM processors for embedded systems. Its
Cortex™-M3 32-bit RISC core operating at a 20-MHz frequency brings great performance
and excellent code compacity to the application thanks to the Thumb®-2 instruction set.

The high-speed embedded Flash 256 Kbyte memory introduces more flexibility to the
system.

The ST32F256 also offers a serial communication interface fully compatible with the ISO
7816-3 standard (T=0, T=1) for smartcard applications.

Two general purpose 16-bit timers are available.

A hardware Data Encryption Standard (DES) accelerator can be used to the user to
optimize the application performance. A software library is provided for Advanced
Encryption Standard (AES) implementation.

The ST32F family operates in the –25 to +85°C temperature range and 1.8V, 3V and 5V
supply voltage ranges. A comprehensive range of power-saving modes enables the design
of efficient low-power applications.

Figure 1. ST32F256 block diagram

2/4 Doc ID 15925 Rev 1