ATA5795C
Embedded AVR Microcontroller Including RF Transmitter
and Immobilizer LF Functionality for Remote Keyless
Entry
DATASHEET
Features
●
System solution for immobilizer and remote keyless entry functionality
●
Optional integrated open source immobilizer software stack supports automotive
immobilizer applications (CMMI certified)
●
Integrated ultra-low power flash Atmel
®
AVR
®
(8-bit) microcontroller
●
2112-byte EEPROM
●
32-bit unique device identification number
●
Available in small 5x5 QFN32 pin package
Contactless Transponder
●
LF contactless transponder operation in passive and active modes
●
Integrated codecs for enhanced LF communication range
●
Ultra low-power AES-128 cryptographic engine for use of immobilizer and RKE
applications
●
Access protected area for two 128-bit secret keys for device authentication
●
Optional one 128-bit transport key for initial configuration
●
LF receiver data integrity check (CRC-4/CRC-8)
RF Transmitter
●
Fully integrated fractional-N PLL, VCO and loop filter covering 315MHz and
433MHz (software programmable)
●
Output power programmable from –0.5 to +12.5dBm
●
Supports ASK and FSK modulation with data rate up to 40Kbit/s
●
Extended battery lifetime due to fast start-up time, low operating voltage and low
supply current
This is a summary document.
The complete document is
available under NDA. For more
information, please contact
your local Atmel sales office.
9182ES-RKE-11/14
Ultra-low-power AVR Microcontroller
●
8Kbyte flash program memory (including 2KB of immobilizer software stack)
●
2112-byte EEPROM – includes protected user data and device configuration data (64Bytes)
●
Error correction code (ECC) engine protects flash and EEPROM
●
512Bytes of SRAM
●
Four GP timers
●
●
●
●
T0: Flexible WD and interval timers
T1: 15-bit interval timer
T2: Asynchronous 8-bit timer/counter with output compare
T3: Asynchronous 8-bit timer/counter with output compare and input capture
●
Power management unit
●
System clock management and monitoring functions
●
POR and brown-out detection
●
Programmable voltage monitor
●
RTC and two internal system clock RC oscillators with f
1
= 125kHz, f
2
= 4MHz
●
SPI, TM/SSI, IR digital interfaces; dW 1-wire debug IF with AVR development tools
●
Very low power consumption:
●
●
●
●
Active: 50µA (Sys_Clk at 125kHz)
Idle: < 70µA (Sys_Clk at 1MHz)
Power-down: 0.8µA
EE(wr): 50µA
●
Wide battery voltage range from 1.9 to 3.6V (in contact mode)
●
–40 to +85°C operation temperature
●
Automotive grade C compiler
2
ATA5795C [DATASHEET]
9182ES–RKE–11/14
1.
Description
Atmel
®
ATA5795C is a smart remote keyless entry (RKE) device that includes an embedded ultra-low-power AVR
®
8-bit
microcontroller, a fractional-N RF transmitter and an LF immobilizer interface in a single QFN32 package.
Furthermore, the device has an integrated AES-128 cryptography hardware engine, which is accessible by both the
immobilizer and the RKE unit. The immobilizer interface can run in contactless mode, allowing energy supply and data
transmission via the LF link.
The Atmel ATA5795C is designed for automotive applications that necessitate both immobilization and remote keyless entry
functions in one single key. It conforms to requirements of extremely low power consumption and provides all the necessary
circuitry for the entire application.
1.1
System Block Diagram
Figure 1-1. System Block Diagram
Key
Battery
VBAT
Car
C
BUF
T-Coil
16 15 14 13 12 11 10 9
17
18
19
20
21
22
23
8
7
6
RF
AVR
RF-Receiver:
ATA5723/24/28
ATA5780
ATA5795C
5
4
3
2
1
RF-
Loop antenna
24
25 26 27 28 29 30 31 32
Transponder
Base Station:
U2270, ATA5272
ATA5795C [DATASHEET]
9182ES–RKE–11/14
3
1.2
Atmel ATA5795C Block Diagram
Figure 1-2. Atmel ATA5795C Block Diagram
VSRF
ECIN
VBAT
A4P
A4N
Power
Management
AFE
Contactless
Interface/
Transponder
SPI
EEPROM/
2.1KB
FRC-Oscillator
VCC
RTC
Clock
Management
and
Monitoring
XTO
XTO1
XTO2
Frac.-N
PLL
Watchdog
Oscillator
PC0
Volt. Monitor
PD7/TM3
PD6/TM2
PD5/TM1
PD4/ECIN0
PD3
PD2/TEI
PD1/T3ICP
PD0/INT0
XTAL2
XTAL1
Debug-
WIRE
Timer Block
SRAM/512B
Flash/8KB
POR/BOD
and
Reset
IR-Driver
Watchdog
Timer
Power
Amplifier
RF-Transmitter
VCO
AVR-Core
Digital
Control
CRC-Module
IO-Ports
ANT1
ANT2
Crypto Unit
PB3/MISO
PB2/MOSI
PB5/TM5
PB4/TM4
PB1/SCK
PB0/NSS
1.3
Pin Configurations
Figure 1-3. Pin Out for QFN 32 Package
XTO2
ANT1
ANT2
PB6
PB7
PB0
PB1
PB2
32 31 30 29 28 27 26 25
TME
XTO1
VSRF
GNDRF
NRESET
PC0
A4N
A4P
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16
24
23
22
PB3
PD3
PD4
PD5
PD6
PD7
PB4
PB5
Atmel
ATA5795C
21
20
19
18
17
XTAL1
4
ATA5795C [DATASHEET]
9182ES–RKE–11/14
XTAL2
VBAT
GND
PD0
PD1
PD2
VCC
NRESET(DW)
GNDRF
PB7
PB6
GND
TME
Table 1-1.
Pin
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Pin Description
Pin Name
TME
XTO1
VSRF
GNDRF
NRESET
PC0
A4N
A4P
VBAT
PD0
PD1
PD2
VCC
XTAL1
GND
XTAL2
PB5
PB4
PD7
PD6
PD5
PD4
PD3
PB3
PB2
PB1
ANT2
ANT1
PB0
PB7
PB6
XTO2
Alternate
Function 1
-
-
-
-
dW
-
-
-
-
INT0
T3ICP
TEI
-
-
-
-
TM5
TM4
TM3
TM2
TM1
ECIN0
-
MISO
MOSI
SCK
-
-
NSS
-
-
-
Alternate
Function 2 Function
-
-
-
-
-
-
-
-
-
PCINT8
PCINT9
PCINT10
-
-
-
-
PCINT5
PCINT4
PCINT15
PCINT14
PCINT13
PCINT12
PCINT11
PCINT3
PCINT2
PCINT1
-
-
PCINT0
PCINT7
PCINT6
-
Test mode enable
Connection for RF crystal
Power supply voltage RF
Power supply ground RF
Reset input / debugWire interface
I/O port
Input pin for transponder AFE
Input pin for transponder AFE
Power supply voltage for battery
I/O port / external interrupt input 0
I/O port / timer 3 external capture input
I/O port / external timer input clock
Power supply voltage for the microcontroller.
A capacitor with capacitance C
BUF
must be
connected at this pin to buffer the voltage during
field supply and block the microcontroller VCC.
32kHz crystal oscillator input pin
Power supply ground
32kHz crystal oscillator output pin
I/O port / timer modulator pin 5
I/O port / timer modulator pin 4
I/O port / timer modulator pin 3
I/O port / timer modulator pin 2
I/O port / timer modulator pin 1
I/O port / external clock input 0
I/O port
I/O port / SPI
I/O port / SPI
I/O port / SPI
RF antenna 2
RF antenna 1
I/O port / SPI
I/O port
I/O port
Connection for RF crystal
Port B5
Port B4
Port D7
Port D6
Port D5
Port D4
Port D3
Port B3
Port B2
Port B1
RF - pin
RF - pin
Port B0
Port B7
Port B6
RF - pin
Port D0
Port D1
Port D2
Port C0
RF - pin
RF - pin
RF - pin
Comment
ATA5795C [DATASHEET]
9182ES–RKE–11/14
5
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