User Manual
Table Of Contents
- 1 Introduction
- 2 Pin Configurations
- 3 CPU
- 4 Memory Organisation
- 5 System Clocks
- 6 Reset
- 7 Interrupt System
- 8 Wireless Transceiver
- 9 Digital Input/Output
- 10 Serial Peripheral Interface
- 11 Timers
- 12 Pulse Counters
- 13 Serial Communications
- 14 JTAG Debug Interface
- 15 Two-Wire Serial Interface
- 16 Four-Wire Digital Audio Interface
- 17 Random Number Generator
- 18 Sample FIFO
- 19 Intelligent Peripheral Interface
- 20 Analogue Peripherals
- 21 Power Management and Sleep Modes
- 22 Electrical Characteristics
- 22.1 Maximum Ratings
- 22.2 DC Electrical Characteristics
- 22.3 AC Characteristics
- 22.3.1 Reset and Voltage Brown-Out
- 22.3.2 SPI MasterTiming
- 22.3.3 Intelligent Peripheral (SPI Slave) Timing
- 22.3.4 Two-wire Serial Interface
- 22.3.5 Four-Wire Digital Audio Interface
- 22.3.6 Wakeup and Boot Load Timings
- 22.3.7 Bandgap Reference
- 22.3.8 Analogue to Digital Converters
- 22.3.9 Digital to Analogue Converters
- 22.3.10 Comparators
- 22.3.11 32kHz RC Oscillator
- 22.3.12 32kHz Crystal Oscillator
- 22.3.13 32MHz Crystal Oscillator
- 22.3.14 24MHz RC Oscillator
- 22.3.15 Temperature Sensor
- 22.3.16 Radio Transceiver
- Appendix A Mechanical and Ordering Information
- Appendix B Development Support
Jennic
© Jennic 2009 JN-DS-JN5148-001 1v2 31
Preliminary
Some protocols (for example ZigBee) require that security operations can be performed on buffered data rather than
in-line. A hardware implementation of the encryption engine significantly speeds up the processing of the contents of
these buffers. The AES library for the JN5148 provides operations that utilise the encryption engine in the device and
allow the contents of memory buffers to be transformed. Information such as the type of security operation to be
performed and the encrypt/decrypt key to be used must also be provided.
Processor
Interface
In-line
Interface
Arbiter
AES
Block
Encrpytion
Controller
AES
Encoder
Key Generation
Figure 18: Security Coprocessor Architecture
8.5 Location Awareness
The JN5148 provides the ability for an application to obtain the Time Of Flight (TOF) between two network nodes.
The TOF information is an alternative metric to that of the existing Energy Detect value (RSSI) that has been typically
used for calculating the relative inter-nodal separation, for subsequent use in a location awareness system.
For short ranges RSSI will typically give a better accuracy than TOF, however for distances above 5 to 10 meters
TOF will offer significant improvements in accuracy compared to RSSI. In general, the RSSI error scales with
distance, such that if the distance doubles then the error doubles.
8.6 Higher Data Rates
To support the demands of applications that require high data throughputs such as in audio or data streaming
applications, the JN5148 supports higher data rate modes that offer 500kbps or 667kbps on air transmission rates.
The switching between standard and higher data rates is controlled via software, When operating in a higher data
rate mode standard IEEE802.15.4 features, such as clear channel assessment, can still be used. This allows the
JN5148 in a higher data rate mode to co-exist in an IEEE802.15.4 based network (adhering to the correct bit rates
and frame timing etc.) whilst at the same time providing the benefit of the higher data rate where required.
When operating in a higher data rate mode, the sensitivity of the radio will be reduced.