
Features
ST21NFCA operating modes supported:
■ Card emulation
■ Reader/Writer
■ Peer-to-peer communication
ST21NFCA
Near field communication microcontroller
Data brief
Hardware features
■ Enhanced 8/16-bit CPU core
■ 112 Kbytes of ROM
■ 4 Kbytes of RAM
■ 36 Kbytes of EEPROM
■ High integrated analog front end (AFE) for RF
transmission and reception including automatic
card and field detection modes
■ Full Power and Low Power modes supported
■ Optimized power consumption modes
■ SIM and ST21NFCA power management
functions
■ 3V power supply
■ Supports Class B and C for UICC (Universal
Integrated Circuit Card)
RF communications
■ ISO/IEC 14443 A&B in both PICC (Proximity
Card) and PCD (Proximity Coupling Device)
modes
■ ISO/IEC 15693 in VCD (Vicinity Coupling
Device) mode
■ ISO/IEC 18092 (NFCIP-1)
■ NFC Forum tags types 1 to 4 supported
(Topaz®, MIFARE® Ultralight, Jewel®,
FeliCa™ Open Tag, ST23YR18/80 with Type 4
applet)
Host communication interfaces
■ Single Wire Protocol (SWP) interface with
support for contactless tunneling mode (CLT)
2
■ I
C Slave interface
■ SPI Slave interface
■ Interrupt mode for SPI and I
2
C interfaces
Software features
■ Includes all drivers supporting the handling and
host protocols for contact and contactless
interfaces
■ Includes complete firmware driving switch
modes between operating modes and host
controller interface functions (based on [ETSI
TS 102 622 HCI])
■ Product configuration/patchability via I
2
C and
SPI
■ Automatic AID (Application Identifier) routing
■ Dual Secure Element support
Evaluation kit
■ An evaluation board is available to evaluate the
advantages of the ST21NFCA router IC and to
facilitate the development of NFC, Contactless
and RFID applications. Please contact ST
sales office for more information.
February 2012 Doc ID 14403 Rev 3 1/5
For further information contact your local STMicroelectronics sales office.
www.st.com
5

Description ST21NFCA
1 Description
The ST21NFCA is a standalone chip designed for supporting 13.56 MHz contactless
communication, including Near Field Communication (NFC) functions in three operating
modes: card emulation, reader/writer and peer-to-peer communication.
The ST21NFCA is designed for an optimized integration with the standard communication
links for a cell phone.
Figure 1. Mobile phone communication links
The ST21NFCA system-on-chip includes embedded firmware which handles:
● ISO/IEC 14443 A&B and ISO/IEC 18092 (NFCIP-1) in Card Emulation modes as well
as Reader modes
● Polling loop for RF card and RF reader detection
● Host Controller Interface functions (HCI based on the ETSI specification)
In addition, the embedded firmware and associated hardware IPs support handling and
protocol for the various interfaces:
● Single Wire Protocol (SWP) interface fully compliant with [ETSI_SWP]
2
● I
C Slave interface up to 400 kHz fully compliant with [I2C] fast mode
● SPI Slave interface up to 1 MHz
The ST21NFCA is a serial access circuit based on a 8/16-bit CPU core. Operations are
synchronized with an internally generated clock issued by the Clock Generator module.
The CPU includes the Arithmetic Logic Unit (ALU), the control logic and registers controlled
by the ST21NFCA firmware. The CPU interfaces with the on-chip RAM, ROM and EEPROM
memories via a 24-bit internal bus offering 16 MBytes of linear addressing space.
2/5 Doc ID 14403 Rev 3

ST21NFCA Description
This device also includes a True Random Number Generator (TRNG), three 8-bit fully
programmable timers, a Cyclic Redundancy Check (CRC3309) module, and a Data
Encryption Standard (DES) accelerator.
Thanks to an enhanced power switch system, the ST21NFCA is able to support several
power supply sources (Full and Low Power modes) which manage the power management
of the device and its associated UICC.
Figure 2. ST21NFCA block diagram
VCC_UICC_IN
VCC_UICC_OUT
GND
VPS_MAIN from PMU
CD2
VBAT
SWP I2C Wakeup SPI ISO/IEC 7816
Power
Manage-
ment
8-bit
ST21
CPU
SWP
SDA
VPS_MAIN
EEPROM
36 Kbytes
SCL
VPS_MAIN from PMU
VPS_TX GND_TX
ST21NFCA
User ROM
112 Kbytes
Peripherals
NSS
IRQ_OUT
SCK
CD1
Management
4 Kbytes
MOSI
Clock
MISO
RAM
IART
GPIO1
NC
CA1
CA3
GND_RX
CQ1
27.12 MHz
CQ2
CA2
Ai18125
XIN
XOUT
TX1
Analog Frontend
GPIO2
VDC
TX2
RX1
RX2
CT1
EXT_CAP
Peripherals
1.1 Firmware overview
ST21NFCA embedded firmware manages NFC operating functions and provides an
interface for communication with different hosts (Application Processor, USIM, eSE, etc.).
This firmware includes:
■ RF drivers for vicinity and proximity standards in Card Emulation and Reader/Writer
modes.
■ Host Controller Interface (HCI), an interface protocol module that manages
communication channels between all devices integrated inside mobile phone, and defined
in the [ETSI HCI] specification.
This interface uses HCP over SHDLC stack protocol:
■ Over I
■ Over SWP (CLF in Master mode) for communication with the SIM (UICC).
2
C or SPI (CLF in Slave mode) for communication with a host processor).
Doc ID 14403 Rev 3 3/5

Revision history ST21NFCA
Figure 3. Host controller block diagram
2 Revision history
Table 1. Document revision history
Date Revision Changes
8-Feb-2008 1 Initial release.
27-Jan-2012 2
21-Feb-2012 3 Updated evaluation kit information.
4/5 Doc ID 14403 Rev 3
Modified Features, Section 1.1: Firmware overview, Figure 1,
Figure 2, and Figure 3.

ST21NFCA
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