Technical Data Sheet

SPIRIT1
Low data rate, low power sub-1GHz transceiver
Datasheet - production data
• Wake-up on internal timer and wake-up on
external event
• Flexible packet length with dynamic payload
length
• Sync word detection
• Address check
QFN20
• Automatic CRC handling
• FEC with interleaving
Features
• Digital RSSI output
• Frequency bands: 150-174 MHz, 300-348
MHz, 387-470 MHz, 779-956 MHz
• Modulation schemes: 2-FSK, GFSK, MSK,
GMSK, OOK, and ASK
• Air data rate from 1 to 500 kbps
• Very low power consumption (9 mA RX and 21
mA TX at +11 dBm)
• Programmable RX digital filter from 1 kHz to
800 kHz
• Programmable carrier sense (CS) indicator
• Automatic clear channel assessment (CCA)
before transmitting (for listen-before-talk
systems). Embedded CSMA/CA protocol
• Programmable preamble quality indicator
(PQI)
• Link quality indication (LQI)
• Whitening and de-whitening of data
• Programmable channel spacing (12.5 kHz
min.)
• Wireless M-BUS, EN 300 220, FCC CFR47 15
(15.205, 15.209, 15.231, 15.247, 15.249), and
ARIB STD T-67, T93, T-108 compliant
• Excellent performance of receiver sensitivity (118 dBm), selectivity, and blocking
• QFN20 4x4 mm RoHS package
• Programmable output power up to +16 dBm
• Operating temperature range from -40 °C to
105 °C
• Fast startup and frequency synthesizer settling
time (6 µs)
Applications
• Frequency offset compensation
• AMR (automatic meter reading)
• Integrated temperature sensor
• Battery indicator and low battery detector
• RX and TX FIFO buffer (96 bytes each)
• Home and building automation
• WSN (wireless sensors network)
• Industrial monitoring and control
• Configurability via SPI interface
• Automatic acknowledgment, retransmission,
and timeout protocol engine
• Wireless fire and security alarm systems
• Point-to-point wireless link
• AES 128-bit encryption co-processor
Table 1. Device summary
• Antenna diversity algorithm
• Fully integrated ultra low power RC oscillator
June 2015
This is information on a product in full production.
Order code
Package
Packing
SPIRIT1QTR
QFN20
Tape and reel
DocID022758 Rev 8
1/104
www.st.com
Contents
SPIRIT1
Contents
1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3
Typical application diagram and pin description . . . . . . . . . . . . . . . . . 11
3.1
Typical application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4
Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5
Absolute maximum ratings and thermal data . . . . . . . . . . . . . . . . . . . 16
6
Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7
6.1
General characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.2
Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.2.1
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.2.2
Digital SPI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6.2.3
RF receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.2.4
RF transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.2.5
Crystal oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.2.6
Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.1
Reset sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
7.2
Timer usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.3
Low duty cycle reload mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.3.1
7.4
8
CSMA/CA engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Block description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.1
Power management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.1.1
2/104
LDC mode with automatically acknowledgement. . . . . . . . . . . . . . . . . . 38
Switching frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.2
Power-on-reset (POR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.3
Low battery indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8.4
Voltage reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
DocID022758 Rev 8
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Contents
8.5
Oscillator and RF synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
8.6
RCO: features and calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
8.6.1
9
RC oscillator calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
8.7
AGC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
8.8
AFC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.9
Symbol timing recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.9.1
DLL mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
8.9.2
PLL mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
8.10
Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
8.11
Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
8.12
Temperature sensors (TS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
8.13
AES encryption co-processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Transmission and reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
9.1
PA configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
9.2
RF channel frequency settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
9.3
RX timeout management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.4
Intermediate frequency setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
9.5
Modulation scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
9.6
9.7
9.5.1
Data rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
9.5.2
RX channel bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Data coding and integrity check process . . . . . . . . . . . . . . . . . . . . . . . . . 61
9.6.1
FEC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
9.6.2
CRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
9.6.3
Data whitening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
9.6.4
Data padding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Packet handler engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
9.7.1
STack packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
9.7.2
Wireless M-Bus packet (W M-BUS, EN13757-4) . . . . . . . . . . . . . . . . . . 64
9.7.3
Basic packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
9.7.4
Automatic packet filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
9.7.5
Link layer protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
9.8
Data modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
9.9
Data FIFO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
9.10
Receiver quality indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
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Contents
10
SPIRIT1
9.10.1
RSSI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
9.10.2
Carrier sense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
9.10.3
LQI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
9.10.4
PQI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
9.10.5
SQI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
9.11
Antenna diversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
9.12
Frequency hopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
MCU interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
10.1
Serial peripheral interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
10.2
Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
10.3
GPIOs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
10.4
MCU clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
11
Register table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
12
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
13
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
4/104
DocID022758 Rev 8
SPIRIT1
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Table 11.
Table 12.
Table 13.
Table 14.
Table 15.
Table 16.
Table 17.
Table 18.
Table 19.
Table 20.
Table 21.
Table 22.
Table 23.
Table 24.
Table 25.
Table 26.
Table 27.
Table 28.
Table 29.
Table 30.
Table 31.
Table 32.
Table 33.
Table 34.
Table 35.
Table 36.
Table 37.
Table 38.
Table 39.
Table 40.
Table 41.
Table 42.
Table 43.
Table 44.
Table 45.
Table 46.
Table 47.
Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Description of the external components of the typical application diagram . . . . . . . . . . . . 13
BOM for different bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Pinout description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
General characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Power consumption static modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Power consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Digital SPI input and output (SDO, SDI, SCLK, CSn, and SDN) and GPIO specification (GPIO_1-4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
RF receiver characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
RF receiver characteristics - sensitivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
RF transmitter characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Crystal oscillator characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Ultra low power RC oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
N-Fractional Σ∆ frequency synthesizer characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Analog temperature sensor characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Battery indicator and low battery detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Commands list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
POR parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
SPIRIT1 timers description and duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
SMPS configuration settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Programmability of trans-conductance at startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
CP word look-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
RC calibrated speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
PA_level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Frequency threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
RX timeout stop condition configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
IF_OFFSET settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
CHFLT_M and CHFLT_E value for channel filter bandwidth (in kHz, for fclk = 24 MHz) . . 60
CHFLT_M and CHFLT_E value for channel filter bandwidth (in kHz, for fclk = 26 MHz) . . 60
Packet configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
SPI interface timing requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Interrupts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Digital outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Digital inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
MCU_CK_CONF configuration register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
MCU clock vs. state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
General configuration registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Radio configuration registers (analog blocks). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Radio configuration registers (digital blocks) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Packet/protocol configuration registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Frequently used registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
QFN20 (4 x 4 mm.) mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
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List of tables
Table 48.
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SPIRIT1
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
DocID022758 Rev 8
SPIRIT1
List of figures
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
SPIRIT1 block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Suggested application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Application diagram for Tx boost mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Application diagram for SMPS OFF mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Diagram and transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Power-on reset timing and limits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
LDCR for Tx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
LDCR for Rx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
CSMA flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Shaping of ASK signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Output power ramping configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
LFSR block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Threshold of the linear FIFO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
SPI “write” operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
SPI “read” operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
SPI “command” operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
QFN20 (4 x 4 mm.) drawing dimension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
DocID022758 Rev 8
7/104
104
Description
1
SPIRIT1
Description
The SPIRIT1 is a very low-power RF transceiver, intended for RF wireless applications in
the sub-1 GHz band. It is designed to operate both in the license-free ISM and SRD
frequency bands at 169, 315, 433, 868, and 915 MHz, but can also be programmed to
operate at other additional frequencies in the 300-348 MHz, 387-470 MHz, and 779-956
MHz bands. The air data rate is programmable from 1 to 500 kbps, and the SPIRIT1 can be
used in systems with channel spacing of 12.5/25 kHz, complying with the EN 300 220
standard. It uses a very small number of discrete external components and integrates a
configurable baseband modem, which supports data management, modulation, and
demodulation. The data management handles the data in the proprietary fully
programmable packet format also allows the M-Bus standard compliance format (all
performance classes).
However, the SPIRIT1 can perform cyclic redundancy checks on the data as well as FEC
encoding/decoding on the packets. The SPIRIT1 provides an optional automatic
acknowledgement, retransmission, and timeout protocol engine in order to reduce overall
system costs by handling all the high-speed link layer operations.
Moreover, the SPIRIT1 supports an embedded CSMA/CA engine. An AES 128-bit
encryption co-processor is available for secure data transfer. The SPIRIT1 fully supports
antenna diversity with an integrated antenna switching control algorithm. The SPIRIT1
supports different modulation schemes: 2-FSK, GFSK, OOK, ASK, and MSK.
Transmitted/received data bytes are buffered in two different three-level FIFOs (TX FIFO
and RX FIFO), accessible via the SPI interface for host processing.
8/104
DocID022758 Rev 8
SPIRIT1
Introduction
A simplified block diagram of the SPIRIT1 is shown in Figure 1.
Figure 1. SPIRIT1 block diagram
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Introduction
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The receiver architecture is low-IF conversion. The received RF signal is amplified by a twostage low-noise amplifier (LNA) and down-converted in quadrature (I and Q) to the
intermediate frequency (IF). LNA and IF amplifiers make up the RX front-end (RXFE) and
have programmable gain. At IF, I/Q signals are digitized by ADCs. The demodulated data is
then provided to an external MCU either through the 96-byte RX FIFO, readable via SPI, or
directly using a programmable GPIO pin. A 128-bit AES co-processor is available to perform
(offline) data encryption/decryption to secure data transfer.
The transmitter part of the SPIRIT1 is based on direct synthesis of the RF frequency. The
power amplifier (PA) input is the LO generated by the RF synthesizer, while the output level
can be configured between -30 dBm and +11 dBm in 0.5 dB steps. The data to be
transmitted can be provided by an external MCU either through the 96-byte TX FIFO
writable via SPI, or directly using a programmable GPIO pin. The SPIRIT1 supports
frequency hopping, TX/RX and antenna diversity switch control, extending the link range
and improving performance.
The SPIRIT1 has a very efficient power management (PM) system.
DocID022758 Rev 8
9/104
104
Introduction
SPIRIT1
An integrated switched mode power supply (SMPS) regulator allows operation from a
battery voltage ranging from +1.8 V to +3.6 V, and with power conversion efficiency of at
least 80%.
A crystal must be connected between XIN and XOUT. It is digitally configurable to operate
with different crystals. As an alternative, an external clock signal can be used to feed XIN for
proper operation. The SPIRIT1 also has an integrated low-power RC oscillator, generating
the 34.7 kHz signal used as a clock for the slowest timeouts (i.e. sleeping and backoff).
A standard 4-pin SPI bus is used to communicate with the external MCU. Four configurable
general purpose I/Os are available.
10/104
DocID022758 Rev 8
SPIRIT1
Typical application diagram and pin description
3
Typical application diagram and pin description
3.1
Typical application diagram
This section describes different application diagram of SPIRIT1 that can be used according
to customer needs. In particular Figure 2 shows the default configuration, Figure 3 shows
the TX boost mode configuration and Figure 4 shows the SMPS off configuration. The
default configuration is giving the best power consumption figures. The TX boost mode
configuration is used to increase TX output power and the SMPS off configuration is used to
enhance sensitivity at the expense of power consumption. When using SMPS off
configuration, SMPS should disabled by setting to1 bit DISABLE_SMPS in PM_CONFIG
register.
Figure 2. Suggested application diagram
1.8V÷3.6V power supply
C13
VBAT 16
VREG 17
GPIO_3 18
GPIO_2 19
GPIO_1 20
1 GPIO_0
C12
SDN 15
L7
2 MISO
SPIRIT1
SMPS Ext1 14
3 MOSI
DIE ATTACH PAD:
SMPS Ext2 13
C11
L8
L0
TX 12
4 SCLK
C15
GND_PA 11
10 RFn
9 RFp
7 XIN
8 VBAT
5 CSn
6 XOUT
DIGITAL INTERFACE
C0
L1
C1
L4
L9
L6
C10
C2
C5
XTAL
C9
L2
C6
C4
C14
L3
C3
L5
C7
C8
Antenna
(50Ω)
AM09258V1
DocID022758 Rev 8
11/104
104
Typical application diagram and pin description
SPIRIT1
Figure 3. Application diagram for Tx boost mode
1.8V÷3.6V power supply
C13
C12
SDN 15
L7
2 MISO
SPIRIT1
SMPS Ext1 14
3 MOSI
DIE ATTACH PAD:
SMPS Ext2 13
C11
L8
1.8V÷3.6V power supply
VBAT 16
VREG 17
GPIO_3 18
GPIO_2 19
1 GPIO_0
GPIO_1 20
DIGITAL INTERFACE
C0
L0
4 SCLK
TX 12
C15
GND_PA 11
10 RFn
9 RFp
8 VBAT
7 XIN
6 XOUT
5 CSn
L1
C1
L4
L9
L6
C10
C2
C5
XTAL
C9
L2
C6
C4
C14
L3
C3
L5
C7
C8
Antenna
(50Ω)
AM09258V2
12/104
DocID022758 Rev 8
SPIRIT1
Typical application diagram and pin description
Figure 4. Application diagram for SMPS OFF mode
1.8V÷3.6V power supply
1.4V÷1.8V
C13
VBAT 16
VREG 17
GPIO_3 18
GPIO_2 19
1 GPIO_0
GPIO_1 20
DIGITAL INTERFACE
C0
C12
SDN 15
C11
2 MISO
SPIRIT1
SMPS Ext1 14
3 MOSI
DIE ATTACH PAD:
SMPS Ext2 13
L0
4 SCLK
TX 12
C15
GND_PA 11
10 RFn
9 RFp
8 VBAT
7 XIN
6 XOUT
5 CSn
L1
C1
L4
L9
L6
C10
C2
C5
XTAL
C9
L2
C6
C4
C14
L3
C3
L5
C7
C8
Antenna
(50Ω)
AM09258V3
Table 2. Description of the external components of the typical application diagram
Components
C0
Description
Decoupling capacitor for on-chip voltage regulator to digital part
C1, C2, C3, C14, C15 RF LC filter/matching capacitors
C4, C5
C6, C7, C8
RF balun/matching capacitors
RF balun/matching DC blocking capacitors
C9, C10
Crystal loading capacitors
C11, C12, C13
SMPS LC filter capacitor
L0
L1, L2, L3, L9
L4, L5, L6
RF choke inductor
RF LC filter/matching inductors
RF balun/matching inductors
L7, L8
SMPS LC filter inductor
XTAL
24, 26, 48, 52 MHz
Table 2 assumes to cover all the frequency bands using a set of different as shown in
Table 3: BOM for different bands.
DocID022758 Rev 8
13/104
104
Typical application diagram and pin description
SPIRIT1
Table 3. BOM for different bands
Ref
design
(1)
170 MHz band
315 MHz band
433 MHz band
868 MHz band
915/922 MHz band
STEVALIKRV001V1
STEVALIKRV001V2
STEVALIKRV001V3
STEVALIKRV001V4
STEVAL-IKRV001V5
Comp. Supplier
Value
Supplier
Value
Supplier
Value
Supplier
Value
Supplier
Value
Murata
100nF
Murata
100nF
NE
Murata
7pF
C0
Murata
100nF
Murata
100nF
Murata
100nF
C1
Murata
18pF
Murata
12pF
Murata
8.2pF
C2
Murata
27pF
Murata
27pF
Murata
18pF
Murata
8.2pF
Murata
2.4pF
C3
Murata
4.3pF
Murata
15pF
Murata
10pF
Murata
5.6pF
Murata
3.6pF
NE
Murata
3.9pF
Murata
2.2pF
Murata
2.2pF
Murata
2pF
C4
C5
Murata
8pF
Murata
4.7pF
Murata
3.3pF
Murata
1.8pF
Murata
1.5pF
C6
Murata
220pF
Murata
220pF
Murata
220pF
Murata
220pF
Murata
330pF
C7
Murata
68nH
(inductor)
Murata
220pF
Murata
220pF
Murata
220pF
Murata
220pF
C8
Murata
390pF
Murata
220pF
Murata
220pF
Murata
220pF
Murata
220pF
C9
Murata
12pF
Murata
12pF
Murata
12pF
Murata
12pF
Murata
12pF
C10
Murata
10pF
Murata
10pF
Murata
10pF
Murata
10pF
Murata
10pF
C11
Murata
1µF
Murata
1µF
Murata
1µF
Murata
470nF
Murata
1µF
C12
Murata
100nF
Murata
100nF
Murata
100nF
Murata
100nF
Murata
100nF
C13
Murata
560pF
Murata
330pF
Murata
330pF
Murata
330pF
Murata
330pF
C14
Murata
220pF
Murata
1.8pF
Murata
1.8pF
Murata
1.2pF
NE
C15
Murata
6.2pF
Murata
1.2pF
NE
NE
L0
Murata
200nH
Murata
220nH
Murata
150nH
Murata
100nH
Murata
100nH
L1
Coilcraft
39nH
Murata
12nH
Murata
8.2nH
Murata
3nH
Murata
3.6nH
L2
Coilcraft
56nH
Murata
12nH
Murata
10nH
0R0
(resistor)
Murata
5.1nH
L3
Murata
3.6pF
(cap.)
Murata
15nH
Murata
10nH
Murata
4.3nH
Tyco
Electronics
0R0
L4
Murata
100nH
Murata
47nH
Murata
39nH
Murata
18nH
Murata
15nH
L5
Murata
47nH
Murata
39nH
Murata
27nH
Murata
18nH
Murata
18nH
NE
Murata
22nH
Murata
15nH
L6
L7
NE
Murata
L8
NE
NE
10µH
Murata
10µH
Murata
10µH
Murata
10µH
Murata
10µH
0R0
(resistor)
Murata
270nH
Murata
100nH
Coilcraft
27nH
Coilcraft
27nH
L9
Coilcraft
51nH
Murata
15nH
Murata
6.2nH
Murata
2.7nH
XTAL
NDK
25 MHz
NDK
50
MHz
NDK
50 or 52
MHz
NDK
50 or 52
MHz
NE
NDK
1. For complete BOM including part numbers, please check the corresponding reference design.
14/104
DocID022758 Rev 8
50 or
52
MHz
SPIRIT1
4
Pinout
Pinout
Table 4. Pinout description
Pin
Name
I/O
Description
1
GPIO_0
I/O
See description of GPIOs below
2
MISO
O
SPI data output pin
3
MOSI
I
SPI data input pin
4
SCLK
I
SPI clock input pin
5
CSn
I
SPI chip select
6
XOUT
O
Crystal oscillator output. Connect to an external 26 MHz crystal or
leave floating if driving the XIN pin with an external signal source
Crystal oscillator input. Connect to an external 26 MHz crystal or to
an external source. If using an external clock source with no crystal,
DC coupling with a nominal 0.2 VDC level is recommended with
minimum AC amplitude of 400 mVpp.
The instantaneous level at input cannot exceed the 0 - 1.4 V range.
7
XIN
I
8
VBAT
VDD
9
RXp
I
10
RXn
I
11
GND_PA
GND
12
TX
O
RF output signal
13
SMPS Ext2
I
Regulated DC-DC voltage input
14
SMPS Ext1
O
DC-DC output pin
Shutdown input pin. 0-VDD V digital input. SDN should be = ‘0’ in all
modes except shutdown mode. When SDN =’1’ the SPIRIT1 is
completely shut down and the contents of the registers are lost. The
GPIO and SPI ports during SHUTDOWN are in HiZ.
+1.8 V to +3.6 V input supply voltage
Differential RF input signal for the LNA. See application diagram for a
typical matching network
Ground for PA.
To be carefully decoupled from other grounds.
15
SDN
I
16
VBAT
VDD
+1.8 V to +3.6 V input supply voltage
17
VREG(1)
VDD
Regulated output voltage. A 100 nF decoupling capacitor is required
18
GPIO3
I/O
19
GPIO2
I/O
20
GPIO1
I/O
21
GND
GND
General purpose I/O that may be configured through the SPI
registers to perform various functions, including:
– MCU clock output
– FIFO status flags
– Wake-up input
– Battery level detector
– TX-RX external switch control
– Antenna diversity control
– Temperature sensor output
Exposed pad ground pin
1. This pin is intended for use with the SPIRIT1 only. It cannot be used to provide supply voltage to other
devices.
DocID022758 Rev 8
15/104
104
Absolute maximum ratings and thermal data
5
SPIRIT1
Absolute maximum ratings and thermal data
Absolute maximum ratings are those values above which damage to the device may occur.
Functional operation under these conditions is not implied. All voltages are referred to GND.
Table 5. Absolute maximum ratings
Pin
Parameter
Value
Unit
Supply voltage and SMPS output
-0.3 to +3.9
V
DC voltage on VREG
-0.3 to +1.4
V
DC voltage on digital input pins
-0.3 to +3.9
V
2
DC voltage on digital output pins
-0.3 to +3.9
V
11
DC voltage on analog pins
-0.3 to +3.9
V
6,7,9,10
DC voltage on RX/XTAL pins
-0.3 to +1.4
V
13
DC voltage on SMPS Ext2 pin
-0.3 to +1.8
V
12
DC voltage on TX pin
-0.3 to +3.9
V
Storage temperature range
-40 to +125
°C
±1.0
KV
8,14,16
17
1,3,4,5,15,18,19,20
TSTG
VESD-HBM
Electrostatic discharge voltage
Table 6. Thermal data
Symbol
Rthj-amb
Parameter
Thermal resistance junction-ambient
QFN20
Unit
45
°C/W
Table 7. Recommended operating conditions
Symbol
VBAT
TA
16/104
Parameter
Min.
Typ.
Max.
Unit
Operating battery supply voltage
1.8
3
3.6
V
Operating ambient temperature range
-40
105
°C
DocID022758 Rev 8
SPIRIT1
Characteristics
6
Characteristics
6.1
General characteristics
Table 8. General characteristics
Symbol
Parameter
Min.
Typ.
150
FREQ
300
Frequency range
-
387
779
Max.
Unit
174
MHz
348
MHz
470
MHz
956
MHz
Air data rate for each modulation scheme.
Note that if "Manchester", "3-out-of-6" and/or FEC encoding/decoding options are
selected, the effective bit rate will be lower.
DR
2-FSK
1
500
kBaud
GMSK (BT=1, BT=0.5)
1
500
kBaud
GFSK (BT=1, BT=0.5)
1
500
kBaud
MSK
1
500
kBaud
OOK/ASK
1
250
kBaud
6.2
Electrical specifications
6.2.1
Electrical characteristics
-
Characteristics measured over recommended operating conditions unless otherwise
specified. Typical values are referred to TA = 25 °C, VBAT = 3.0 V. All performance is referred
to a 50 Ohm antenna connector, via the reference design using application diagram as in
Figure 2, except otherwise noted.
Table 9. Power consumption static modes
Symbol
Parameter
Test conditions
Shutdown
Min.
(1)
Supply current
Sleep
Lock
600
(1)
Ready (default mode)
Max.
Unit
2.5
Standby (1)
IBAT
Typ.
(1)
(1)
850
nA
-
400
µA
4.4
mA
1. See Table 20.
DocID022758 Rev 8
17/104
104
Characteristics
SPIRIT1
Table 10. Power consumption
Symbol
Parameter
Test conditions
SMPS ON
SMPS OFF
9.2
16.9
9.2
16.9
433 MHz
9.2
16.9
RX (1) 868 MHz
9.7
17.6
RX (1) 169 MHz
IBAT
Supply current
RX
(1)
RX
(1)
315 MHz
RX
(1)
915 MHz
9.8
17.6
RX
(1)
922 MHz
9.8
17.9
TX
(1)(2)
+16 dBm 169 MHz
54
TX (1)(2) +16 dBm 315 MHz
52
TX
(1)(2)
+16 dBm 433 MHz
TX
(1)(2)
+15.5 dBm 868 MHz
TX
(1)(2)
+16 dBm 920 MHz
TX (1) +11 dBm 169 MHz
49.3
44
mA
45.2
18
33
+11 dBm 315 MHz
22
37
+11 dBm 433 MHz
19.5
33
+11 dBm 868 MHz
21
41
TX (1) +11 dBm 920 MHz
20
39
TX
(1)
TX
(1)
TX
(1)
Unit
TX
(1)
-8 dBm 169 MHz
6
TX
(1)
-8 dBm 315 MHz
6.5
TX
(1)
-7 dBm 433 MHz
7
TX (1) -7 dBm 868 MHz
7
1. See table Table 20.
2. TX boost mode configuration VBAT = 3.6 V.
6.2.2
Digital SPI
Table 11. Digital SPI input and output (SDO, SDI, SCLK, CSn, and SDN) and GPIO
specification (GPIO_1-4)
Symbol
fclk
Clock frequency
CIN
Port I/O capacitance
TRISE
18/104
Parameter
Rise time
Test condition
Min.
Typ.
1.4
0.1*VDD to 0.9*VDD,
CL=20 pF (low output
current programming)
6.0
0.1*VDD to 0.9*VDD,
CL=20 pF (high output
current programming)
2.5
DocID022758 Rev 8
Max.
Unit
10
MHz
pF
ns
SPIRIT1
Characteristics
Table 11. Digital SPI input and output (SDO, SDI, SCLK, CSn, and SDN) and GPIO
specification (GPIO_1-4) (continued)
Symbol
Parameter
TFALL
Fall time
VIH
Logic high level input
voltage
VIL
Logic low level input
voltage
VOH
VOL
6.2.3
Test condition
Min.
Typ.
0.1*VDD to 0.9*VDD,
CL=20 pF (low output
current programming)
7.0
0.1*VDD to 0.9*VDD,
CL=20 pF (high output
current programming)
2.5
Max.
ns
VDD/2
+0.3
V
VDD/8
+0.3
High level output voltage
IOH = -2.4 mA (-4.2 mA if
high output current
capability is
programmed).
Low level output voltage
IOL = +2.4 mA (+4 mA if
high output current
capability is
programmed).
Unit
(5/8)*
VDD+
0.1
V
V
0.5
V
RF receiver
Characteristics measured over recommended operating conditions unless otherwise
specified. All typical values are referred to TA = 25 °C, VBAT = 3.0 V, no frequency offset in
the RX signal. All performance is referred to a 50 Ohm antenna connector, via the reference
design.
Table 12. RF receiver characteristics
Symbol
RL
Parameter
Return loss
Test condition
Min.
Typ.
169.4-169.475 MHz, 433-435
MHz, 868-868.6 MHz, 310-320
MHz, 902-928 MHz(1)
CHBW
Receiver channel bandwidth
1
PSAT
Saturation 1% PER (packet
length = 20 bytes) FEC
DISABLED
868 MHz 2-GFSK (BT=1) 38.4
kbps (20 kHz dev. CH Filter=100
kHz)
IIP3
Input third order intercept
Input power -50 dBm 915 MHz
DocID022758 Rev 8
Max.
Unit
-10
dB
800
kHz
10
-37
-31
dBm
-26
dBm
19/104
104
Characteristics
SPIRIT1
Table 12. RF receiver characteristics (continued)
Symbol
Parameter
Test condition
Desired channel 3 dB above
sensitivity level. 12.5 kHz Δf, 2FSK 1.2 kbps, (1 kHz dev. CH
Filter=6 kHz)
C/I1-CH(2)
IMREJ(3)
RXBLK(3)
20/104
Typ.
Max.
Unit
49
dB
40
dB
40
dB
Desired channel 3 dB above
sensitivity level. 750 kHz Δf, 2GFSK (BT=1) 250 kbps, (127 kHz
dev. CH Filter=540 kHz)
38
dB
Desired channel 3 dB above
sensitivity level. 25 kHz Δf, 2-FSK
1.2 kbps, (1 kHz dev. CH Filter=6
kHz)
52
dB
43
dB
44
dB
Desired channel 3 dB above
sensitivity level. 1.5 MHz Δf, 2GFSK (BT=1) 250 kbps, (127 kHz
dev. CH Filter=540 kHz)
46
dB
868 MHz 2-GFSK (BT=1) 38.4
Image rejection, 1% PER
kbps (20kHz dev. CH Filter=100
(packet length = 20 bytes)
kHz), desired channel 3 dB above
1% PER (packet length = 20
the sensitivity limit, with IQC
bytes) FEC DISABLED
correction.
47
dB
@ 2 MHz offset, 868 MHz 2GFSK (BT=1) 38.4kbps, desired
channel 3 dB above the sensitivity
limit
-42
dBm
@ 10 MHz offset, 868 MHz 2GFSK (BT=1) 38.4kbps, desired
channel 3 dB above the sensitivity
limit
-40
dBm
Desired channel 3 dB above
sensitivity level. 100 kHz Δf, 2FSK 1.2 kbps, (4.8 kHz dev. CH
Adjacent channel rejection,
1% PER (packet length = 20 Filter=58 kHz)
bytes) FEC DISABLED 868 Desired channel 3 dB above
MHz
sensitivity level. 200 kHz Δf, 2-
GFSK (BT=1) 38.4 kbps, (20 kHz
dev. CH Filter=100 kHz)
C/I2-CH(3)
Min.
Desired channel 3 dB above
sensitivity level. 200 kHz Δf, 2Alternate channel rejection, FSK 1.2 kbps, (4.8 kHz dev. CH
1% PER (packet length = 20 Filter=58 kHz)
bytes)
Desired channel 3 dB above
FEC DISABLED
sensitivity level. 400 kHz Δf, 2868 MHz
GFSK (BT=1) 38.4 kbps, (20 kHz
dev. CH Filter=100 kHz)
Blocking at offset above the
upper band edge and below
the lower band edge 1%
BER
DocID022758 Rev 8
SPIRIT1
Characteristics
Table 12. RF receiver characteristics (continued)
Symbol
Parameter
Spurious emissions
(maximum values according
to ETSI EN 300 220-1)
Spurious emissions (maximum values according to
ARIB STD-T93)
RXSPUR
Spurious emissions (maximum values according to
ARIB STD-T67)
Test condition
Min.
Typ.
RF = 170 MHz, f< 1 GHz
-65
RF = 170 MHz, 1 GHz < f < 4 GHz
-69
RF = 433 MHz - 435 MHz, f< 1
GHz
-63
RF = 433 MHz - 435 MHz, 1 GHz
< f < 4 GHz
-83
RF = 868 MHz, f< 1 GHz
-70
RF = 868 MHz, 1 GHz < f < 6 GHz
-60
RF = 312 MHz - 315 MHz, f< 1
GHz
-69
RF = 312 MHz - 315 MHz, f> 1
GHz
-59
RF = 426 MHz - 470 MHz
-61
Max.
Unit
dBm
RF = 920 MHz - 924 MHz, f< 710
MHz
RF = 920 MHz - 924 MHz, 710
MHz < f < 915 MHz
Spurious emissions (maximum values according to
ARIB STD-T108)
RF = 920 MHz - 924 MHz, 915
MHz < f < 930 MHz
<-70
RF = 920 MHz - 924 MHz, 930
MHz < f < 1 GHz
RF = 920 MHz - 924 MHz, f> 1
GHz
ZIN, RX
Differential Input Impedance
(simulated values)
Max RX gain
RF = 170 MHz
RF = 315 MHz
RF = 433 MHz
RF = 868 MHz
RF = 915 MHz
RF = 922 MHz
-75
200 - j36
180 - j57
170 - j70
118 - j87
113 - j87
113 - j87
Ω
1. Guaranteed in an entire single sub band. Reference design can be different for different application bands.
2. Interferer is CW signal (as specified by ETSI EN 300 220 v1).
3. Blocker is CW signal (as specified by ETSI EN 300 220 v1).
DocID022758 Rev 8
21/104
104
Characteristics
SPIRIT1
Table 13. RF receiver characteristics - sensitivity
Symbol
Parameter
Sensitivity, 1% BER
(according to W-MBUS N
mode specification)
RXSENS
Sensitivity, 1% PER (packet
length = 20 bytes) FEC
DISABLED
22/104
Test condition
SMPS ON SMPS OFF
Unit
169 MHz 2-FSK 1.2kbps
(4 kHz dev. CH Filter=10 kHz)
-117
-123
dBm
169 MHz 2-GFSK (BT=0.5)
2.4kbps (2.4 kHz dev. CH
Filter=7 kHz)
-114
-121
dBm
169 MHz 2-FSK 38.4kbps (20 kHz
dev. CH Filter=100 kHz)
-104
-109
dBm
169 MHz 2-GFSK (BT=0.5)
50 kbps (25 kHz dev. CH
Filter=100 kHz)
-104
-108
dBm
315 MHz 2-FSK 1.2 kbps (4.8 kHz
dev. CH Filter=58 kHz)
-109
-110
dBm
315 MHz MSK 500 kbps (CH
Filter=800 kHz)
-88
-88
dBm
DocID022758 Rev 8
SPIRIT1
Characteristics
Table 13. RF receiver characteristics - sensitivity (continued)
Symbol
Parameter
Sensitivity, 1% PER (packet
length = 20 bytes) FEC
DISABLED
Sensitivity, 1% PER (packet
length = 20 bytes) FEC
DISABLED
RXSENS
Sensitivity, 1% PER (packet
length = 20 bytes) FEC
DISABLED
Sensitivity, 1% PER (packet
length = 20 bytes) FEC
DISABLED
Test condition
SMPS ON SMPS OFF
Unit
433 MHz 2-FSK 1.2 kbps (1 kHz
dev. CH Filter=6 kHz)
-116
-120
dBm
433 MHz 2-GFSK (BT=1) 1.2
kbps (4.8 kHz dev. CH Filter=58
kHz)
-106
-110
dBm
433 MHz 2-GFSK (BT=1) 38.4
kbps (20 kHz dev. CH Filter=100
kHz)
-103
-107
dBm
433 MHz 2-GFSK (BT=1) 250
kbps (127 kHz dev. CH Filter=540
kHz)
-96
-100
dBm
868 MHz 2-FSK 1.2 kbps (1 kHz
dev. CH Filter=6 kHz)
-118
-118
dBm
868 MHz 2-GFSK (BT=1) 1.2
kbps (4.8 kHz dev. CH Filter=58
kHz)
-108
-109
dBm
868 MHz 2-GFSK (BT=1) 38.4
kbps (20 kHz dev. CH Filter=100
kHz)
-105
-106
dBm
868 MHz GFSK (BT=1) 250 kbps
(127 kHz dev. CH Filter=540 kHz)
-98
-99
dBm
868 MHz MSK 250 kbps (CH
Filter=540 kHz)
-93
-94
dBm
915 MHz 2-FSK 1.2 kbps (4.8 kHz
dev. CH Filter=58 kHz)
-108
-109
dBm
915 MHz 2-FSK 38.4 kbps (20
kHz dev. CH Filter =100 kHz)
-106
-106
dBm
915 MHz 2-FSK 250 kbps (127
kHz dev. CH Filter=540 kHz)
-98
-99
dBm
915 MHz MSK 500 kbps (CH
Filter=800 kHz)
-94
-95
dBm
922 MHz 2-FSK 1.2 kbps (4.8 kHz
dev. CH Filter=58 kHz)
-108
-109
dBm
922 MHz 2-FSK 38.4 kbps (20
kHz dev. CH Filter =100 kHz)
-106
-106
dBm
922 MHz 2-FSK 250 kbps (127
kHz dev. CH Filter=540 kHz)
-98
-99
dBm
922 MHz MSK 500 kbps (CH
Filter=800 kHz)
-94
-95
dBm
DocID022758 Rev 8
23/104
104
Characteristics
SPIRIT1
Table 13. RF receiver characteristics - sensitivity (continued)
Symbol
Parameter
Test condition
Sensitivity, 1% PER (packet
length = 20 bytes) FEC
DISABLED(1)
RXSENS
Sensitivity, 1% PER (packet
length = 20 bytes) FEC
DISABLED (2)
SMPS ON SMPS OFF
Unit
433 MHz OOK 1.2 kbps (CH
Filter=6 kHz)
-116
-117
dBm
433 MHz OOK 2.4 kbps (CH
Filter=12 kHz)
-113
-116
dBm
433 MHz OOK 38.4 kbps (CH
Filter=100 kHz)
-99
-100
dBm
433 MHz OOK 250 kbps (CH
Filter=540 kHz)
-87
-87
dBm
868 MHz OOK 1.2 kbps (CH
Filter=6 kHz)
-116
-116
dBm
868 MHz OOK 2.4 kbps (CH
Filter=12 kHz)
-113
-114
dBm
868 MHz OOK 38.4 kbps (CH
Filter=100 kHz)
-100
-100
dBm
868 MHz OOK 250 kbps (CH
Filter=540 kHz)
-90
-90
dBm
1. In OOK modulation, indicated value represents mean power.
6.2.4
RF transmitter
Characteristics measured over recommended operating conditions unless otherwise
specified. All typical values are referred to TA = 25 °C, VBAT = 3.0 V. All performance is
referred to a 50 Ohm antenna connector, via the reference design.
Table 14. RF transmitter characteristics
Symbol
Parameter
Test conditions
Min.
Typ.
PMAX_TX_BO
Maximum output
power(1)
Delivered to a 50 Ohm single-ended
load via reference design using TX
boost mode configuration
-
16
dBm
PMAX
Maximum output
power(1)
Delivered to a 50 Ohm single-ended
load via reference design
-
11
dBm
PMIN
Minimum output power
Delivered to a 50 Ohm single-ended
load via reference design
-
-30
dBm
PSTEP
Output power step
-
0.5
dB
OST
24/104
DocID022758 Rev 8
Max.
Unit
SPIRIT1
Characteristics
Table 14. RF transmitter characteristics (continued)
Symbol
PSPUR,ETSI
Parameter
Unwanted emissions
according to ETSI
EN300 220-1(harmonic
included, using
reference design)
Test conditions
Min.
RF = 170 MHz, frequencies below 1
GHz
Max.
Unit
-
-36
dBm
RF = 170 MHz, Frequencies above 1
GHz
-
< -60
dBm
RF = 170 MHz, frequencies within
47-74, 87.5-108,174-230,470-862
MHz
-
-55
dBm
RF = 434 MHz, frequencies below 1
GHz
-
-42
dBm
RF = 434 MHz, Frequencies above 1
GHz
-
-46
dBm
RF = 434 MHz, frequencies within
47-74, 87.5-108,174-230,470-862
MHz
-
-61
dBm
RF = 868 MHz, frequencies below 1
GHz
-
-51
dBm
RF = 868 MHz, Frequencies above 1
GHz
-
-40
dBm
RF = 868 MHz, frequencies within
47-74, 87.5-108,174-230,470-862
MHz
-
-54
dBm
DocID022758 Rev 8
Typ.
25/104
104
Characteristics
SPIRIT1
Table 14. RF transmitter characteristics (continued)
Symbol
PSPUR,FCC
26/104
Parameter
Unwanted emissions
according to FCC part
15(harmonic included,
using reference design)
Test conditions
Min.
RF = 310-320 MHz, harmonics
(measured with max output power)
Max.
Unit
-
-37
dBm
RF = 310-320 MHz, 1.705 MHz <f<
30 MHz
-
<-60
dBm
RF = 310-320 MHz, 30 MHz <f< 88
MHz
-
<-60
dBm
RF = 310-320 MHz, 88 MHz <f< 216
MHz
-
<-60
dBm
RF = 310-320 MHz, 216 MHz <f<
960 MHz
-
<-60
dBm
RF = 310-320 MHz, 960 MHz <f
-
<-60
dBm
RF = 902-928 MHz, 1.705 MHz <f<
30 MHz (@ max output power)
-
<-70
dBm
RF = 902-928 MHz, 30 MHz <f< 88
MHz (@ max output power)
-
<-70
dBm
RF = 902-928 MHz, 88 MHz <f< 216
MHz (@ max output power)
-
<-70
dBm
RF = 902-928 MHz, 216 MHz <f<
960 MHz (@ max output power)
-
-52
dBm
RF = 902-928 MHz, 960 MHz <f (@
max output power)
-
-41
dBm
2nd and 7th harmonics
-
-25
dBc
DocID022758 Rev 8
Typ.
SPIRIT1
Characteristics
Table 14. RF transmitter characteristics (continued)
Symbol
PSPUR,ARIB
Parameter
Unwanted emissions
according to ARIB
Test conditions
Min.
RF = 312-315 MHz, frequency below
1 GHz (@ max output power,
according to ARIB STD-T93)
Max.
Unit
-
-41
dBm
RF = 312-315 MHz, frequency above
1 GHz (@ max output power,
according to ARIB STD-T93)
-
-48
dBm
RF = 426-470 MHz (@ max output
power, according to ARIB STD-T67)
-
<-40
dBm
RF = 915-917 MHz and
RF = 920-930 MHz, f< 710 MHz (@
max output power, according to ARIB
STD-T108)
-
<-55
dBm
RF = 915-917 MHz and
RF = 920-930 MHz, 710 MHz <f<
915 MHz (@ max output power,
according to ARIB STD-T108)
-
-55
dBm
RF = 915-917 MHz and
RF = 924-930 MHz, 915 MHz <f<
930 MHz (@ max output power,
according to ARIB STD-T108)
-
-36
dBm
RF = 920-924 MHz, 915 MHz <f<
920.3 MHz (@ max output power,
according to ARIB STD-T108)
-
<-36
dBm
RF = 920-924 MHz, 920.3 MHz <f<
924.3 MHz (@ max output power,
according to ARIB STD-T108)
-
-55
dBm
RF = 920-924 MHz, 924.3 MHz <f<
930 MHz (@ max output power,
according to ARIB STD-T108)
-
-36
dBm
RF = 915-917 MHz and
RF = 920-930 MHz, 930 MHz <f<
1000 MHz (@ max output power,
according to ARIB STD-T108)
-
-55
dBm
RF = 915-917 MHz and
RF = 920-930 MHz, 1000 MHz <f<
1215 MHz (@ max output power,
according to ARIB STD-T108)
-
<-60
dBm
RF = 915-917 MHz and
RF = 920-930 MHz, 1215 MHz <f (@
max output power, according to ARIB
STD-T108)
-
-38
dBm
DocID022758 Rev 8
Typ.
27/104
104
Characteristics
SPIRIT1
Table 14. RF transmitter characteristics (continued)
Symbol
Parameter
Test conditions
2nd
PHARM
PALOAD
Harmonics level
Optimum load
impedance (simulated
values)
Typ.
Max.
Unit
RF = 170 MHz,
harmonic (max
power level)
-
RF = 170 MHz, 3rd harmonic (max
power level)
-
-55
RF = 315 MHz, 2nd harmonic (max
power level)
-
-52
RF = 315 MHz, 3rd harmonic (max
power level)
-
-52
RF = 433 MHz, 2nd harmonic (max
power level)
-
-43
RF = 433 MHz, 3rd harmonic (max
power level)
-
-46
RF = 868 MHz, 2nd harmonic (max
power level)
-
-40
RF = 868 MHz, 3rd harmonic (max
power level)
-
-42
RF = 915 MHz, 2nd harmonic (max
power level)
-
-28
RF = 915 MHz, 3rd harmonic (max
power level)
-
-42
RF = 922 MHz, 2nd harmonic (max
power level)
-
-39
RF = 922 MHz, 3rd harmonic (max
power level)
-
-60
170 MHz, using reference design
-
46 +
j36
Ohm
315 MHz, using reference design
-
25 +
j27
Ohm
433 MHz, using reference design
-
29 +
j19
Ohm
868 MHz, using reference design
-
34 - j7
Ohm
915 MHz, using reference design
-
15 +
j28
Ohm
922 MHz, using reference design
-
42 j15
Ohm
1. In ASK/OOK modulation, indicated value represents peak power.
28/104
Min.
DocID022758 Rev 8
-36
dBm
dBc
dBm
dBc
dBm
SPIRIT1
6.2.5
Characteristics
Crystal oscillator
Characteristics measured over recommended operating conditions unless otherwise
specified. All typical values are referred to TA = 25 °C, VBAT = 3.0 V. Frequency synthesizer
characteristics are referred to 915 MHz band. In order to avoid potential RF performance
degradations, the crystal frequency should be chosen to satisfy the following equation:
Equation 1
F ch
nF ch – ROUND  n --------- F ref > 1MHz
 F ref
where n is an integer in the set [1-7,B] (B is band divider).
Table 15. Crystal oscillator characteristics
Symbol
XTALF
FTOL
PNXTAL
TSTART
Parameter
Test conditions
Min.
Range 1
Range 2
Crystal frequency
24
48
Frequency tolerance(1)
Max.
Unit
26
52
MHz
± 40
Minimum requirement on
external reference phase
noise mask (Fxo=26 MHz),
to avoid degradation on
synthesizer phase/noise
Startup time(2)
Typ.
ppm
100 Hz
-90
dBc/Hz
1 kHz
-120
dBc/Hz
10 kHz
-135
dBc/Hz
100 kHz
-140
dBc/Hz
1 MHz
-140
dBc/Hz
220
µs
VBAT=1.8 V, Fxo= 52
MHz
60
120
1. Including initial tolerance, crystal loading, aging, and temperature dependence. The acceptable
crystal tolerance depends on RF frequency and channel spacing/bandwidth.
2. Startup times are crystal dependent. The crystal oscillator transconductance can be tuned to
compensate the variation of crystal oscillator series resistance.
Table 16. Ultra low power RC oscillator
Symbol
RCF
RCTOL
Parameter
Calibrated frequency
Test conditions
Calibrated RC oscillator
frequency is derived from
crystal oscillator frequency.
Digital clock domain 26 MHz
Frequency accuracy after
calibration
Min.
Typ.
Max.
34.7
kHz
±1
DocID022758 Rev 8
Unit
%
29/104
104
Characteristics
SPIRIT1
Table 17. N-Fractional Σ∆ frequency synthesizer characteristics
Symbol
Parameter
Frequency resolution
FRES
PNSYNTH
RF carrier phase noise
(915 MHz band)
TOTIME
PLL turn-on/hop time
SETTIME
PLL RX/TX settling time
CALTIME
PLL calibration time
6.2.6
Test conditions
Min.
Typ.
-
33
10 kHz
-100
-97
-94
dBc/Hz
100 kHz
-104
-101
-99
dBc/Hz
200 kHz
-105
-102
-100
dBc/Hz
500 kHz
-112
-110
-107
dBc/Hz
1 MHz
-120
-118
-116
dBc/Hz
2 MHz
-123
-121
-119
dBc/Hz
60
80
µs
Fxo= 26 MHz high band
Settling time from RX to TX
and from TX to RX
Max.
Unit
Hz
8.5
µs
54
µs
Sensors
Characteristics measured over recommended operating conditions unless otherwise
specified. All typical values are referred to TA = 25 °C, VBAT = 3.0 V.
Table 18. Analog temperature sensor characteristics
Symbol
TERR
TSLOPE
Parameter
Error in temperature
Test conditions
Across all the temperature range
Temperature coefficient
VTS-OUT Output voltage level
TICC
Min.
Current consumption
-
Typ.
Max.
Unit
±2.5
°C
2.5
mV/
°C
0.92
-
V
Buffered output (low output
impedance, about 400 Ohm)
600
µA
Not buffered output (high output
impedance, about 100 kΩ)
10
µA
Table 19. Battery indicator and low battery detector(1)
Symbol
VBLT
30/104
Parameter
Test conditions
Battery level thresholds
Min.
2.1
DocID022758 Rev 8
Typ.
Max.
Unit
2.7
V
SPIRIT1
Characteristics
Table 19. Battery indicator and low battery detector(1)
Symbol
VBOT
Parameter
Brownout threshold
Test conditions
Min.
Typ.
Max.
Unit
Measured in slow battery
variation (static) conditions
(inaccurate)
1.535
V
Measured in slow battery
variation (static) conditions
(accurate)
1.684
V
70
mV
BOThyst Brownout threshold hysteresis
1. For battery powered equipment, the TX does not transmit at a wrong frequency under low battery voltage
conditions. It either remains on channel or stops transmitting. The latter can of course be realized by using a
lock detect and/or by switching off the PA under control of the battery monitor. For testing reasons this control
is enabled/disabled by SPI.
DocID022758 Rev 8
31/104
104
Operating modes
7
SPIRIT1
Operating modes
The SPIRIT1 is provided with a built-in main controller which controls the switching between
the two main operating modes: transmit (TX) and receive (RX).
In shutdown condition (the SPIRIT1 can be switched on/off with the external pin SDN, all
other functions/registers/commands are available through the SPI interface and GPIOs), no
internal supply is generated (in order to have minimum battery leakage), and hence, all
stored data and configurations are lost. The GPIO and SPI ports during SHUTDOWN are in
HiZ. From shutdown, the SPIRIT1 can be switched on from the SDN pin and goes into
READY state, which is the default, where the reference signal from XO is available.
From READY state, the SPIRIT1 can be moved to LOCK state to generate the high
precision LO signal and/or TX or RX modes. Switching from RX to TX and vice versa can
happen only by passing through the LOCK state. This operation is normally managed by
radio control with a single user command (TX or RX). At the end of the operations above,
the SPIRIT1 can return to its default state (READY) and can then be put into a sleeping
condition (SLEEP state), having very low power consumption. If no timeout is required, the
SPIRIT1 can be moved from READY to STANDBY state, which has the lowest possible
current consumption while retaining FIFO, status and configuration registers. To manage the
transitions towards and between these operating modes, the controller works as a statemachine, whose state switching is driven by SPI commands. See Figure 5 for state diagram
and transition time between states.
Figure 5. Diagram and transition
6+87'2:1
67$1'%<
5($'<
6/((3
/2&.
5;7;
$09
The SPIRIT1 radio control has three stable states (READY, STANDBY, LOCK) which may
be defined stable, and they are accessed by the specific commands (respectively READY,
32/104
DocID022758 Rev 8
SPIRIT1
Operating modes
STANDBY, and LOCKRX/LOCKTX), which can be left only if any other command is used.
All other states are transient, which means that, in a typical configuration, the controller
remains in those states, at most for any timeout timer duration. Also the READY and LOCK
states behave as transients when they are not directly accessed with the specific
commands (for example, when LOCK is temporarily used before reaching the TX or RX
states).
Table 20. States
STATE[6:0]
(1)
State/mode
Digital LDO
SPI
Xtal
RF
Synth.
Wake-up
timer
Response time
to(2)
TX
RX
SHUTDOWN
OFF (register
contents lost)
Off
Off
Off
Off
NA
NA
0x40
STANDBY
ON (FIFO and
register
contents
retained)
On
Off
Off
Off
125 µs
125 µs
0x36
SLEEP
On
Off
Off
On
125 µs
125 µs
0x03
READY
(Default)
On
On
Off
Don’t care
50 µs
50 µs
0x0F
LOCK
On
On
On
Don’t care
NA
NA
-
(3)
0x33
RX
On
On
On
Don’t care
15 µs
0x5f
TX
On
On
On
Don’t care
NA
NA
15 µs(3)
1. All others values of STATE[6:0] are invalid and are an indication of an error condition due to bad registers
configuration and/or hardware issue in the application board hosting SPIRIT1.
2. These values are crystal dependent. The values are referred to 52 MHz.
3. These two timings are applicable only for the automatic features (autoACK and CSMA) that automatically
switch the device from RX to TX and viceversa. In case it is needed to pass from TX to RX (or viceversa) by
means of command strobes, it is necessary to abort the current active state and go to the READY state
(please refer to the state machine diagram, figure 5).
Note:
Response time SHUTDOWN to READY is ~650 µs.
READY state is the default state after the power-on reset event. In the steady condition, the
XO is settled and usable as the time reference for RCO calibration, for frequency synthesis,
and as the system clock for the digital circuits.
The TX and RX modes can be activated directly by the MCU using the TX and RX
commands, or automatically if the state machine wakes up from SLEEP mode and some
previous TX or RX is pending. The values are intend to a VCO manual calibration.
In LOCK state the synthesizer is in a locking condition(a). If LOCK state is reached using
either one of the two specific commands (LOCKTX or LOCKRX), the state machine remains
in LOCK state and waits for the next command. This feature can be used by the MCU to
perform preliminary calibrations, as the MCU can read the calibration word in the
a. LOCK state is reached when one of the following events occurs first: lock detector assertion or locking timeout
expiration.
DocID022758 Rev 8
33/104
104
Operating modes
SPIRIT1
RCO_VCO_CALIBR_OUT register and store it in a non-volatile memory, and after that it
requires a further tuning cycle.
When TX is activated by the TX command, the state machine goes into TX state and
remains there until the current packet is fully transmitted or, in the case of direct mode TX,
TXFIFO underflow condition is reached or the SABORT command is applied.
After TX completion, the possible destinations are:
•
TX, if the persistent-TX option is enabled in the PROTOCOL configuration registers
•
PROTOCOL, if some protocol option (e.g. automatic re-transmission) is enabled
•
READY, if TX is completed and no protocol option is in progress.
Similarly, when RX is activated by the RX command, the state machine goes into RX state
and remains there until the packet is successfully received or the RX timeout expires. In
case of direct mode RX, the RX stops when the RXFIFO overflow condition is reached or
the SABORT command is applied. After RX completion, the possible destinations are:
•
RX, if the persistent-RX option is enabled in the PROTOCOL configuration registers
•
PROTOCOL, if some protocol option (e.g. automatic acknowledgement) is enabled
•
READY, if RX is completed and the LDCR mode is not active
•
SLEEP, if RX is completed and the LDCR mode is active.
The SABORT command can always be used in TX or RX state to break any deadlock
condition and the subsequent destination depends on SPIRIT1 programming according to
the description above.
Commands are used in the SPIRIT1 to change the operating mode, to enable/disable
functions, and so on. A command is sent on the SPI interface and may be followed by any
other SPI access without pulling CSn high.
The complete list of commands is reported in Table 21. Note that the command code is the
second byte to be sent on the MOSI pin (the first byte must be 0x80).
Table 21. Commands list
Command
code
Command name
Execution state
0x60
TX
READY
Start to transmit
0x61
RX
READY
Start to receive
0x62
READY
0x63
STANDBY
READY
Go to STANDBY
0x64
SLEEP
READY
Go to SLEEP
0x65
LOCKRX
READY
Go to LOCK state by using the RX configuration of the
synthesizer
0x66
LOCKTX
READY
Go to LOCK state by using the TX configuration of the
synthesizer
0x67
SABORT
TX, RX
Exit from TX or RX states and go to READY state
0x68
LDC_RELOAD
All
Reload the LDC timer with the value stored in the
LDC_PRESCALER/COUNTER registers
34/104
Description
STANDBY, SLEEP,
Go to READY
LOCK
DocID022758 Rev 8
SPIRIT1
Operating modes
Table 21. Commands list (continued)
Command
code
Command name
Execution state
0x69
SEQUENCE_UPDA
TE
All
Reload the packet sequence counter with the value
stored in the PROTOCOL[2] register.
0x6A
AES Enc
All
Start the encryption routine
0x6B
AES Key
All
Start the procedure to compute the key for decryption
0x6C
AES Dec
All
Start decryption using the current key
0x6D
AES KeyDec
All
Compute the key and start decryption
0x70
SRES
All
Reset
0x71
FLUSHRXFIFO
All
Clean the RX FIFO
0x72
FLUSHTXFIFO
All
Clean the TX FIFO
Description
The commands are immediately valid after SPI transfer completion (i.e. no need for any
CSn positive edge).
7.1
Reset sequence
SPIRIT1 is provided with an automatic power-on reset (POR) circuit which generates an
internal RESETN active (low) level for a time TRESET after the VDD reaches the reset
release threshold voltage VRRT (provided that SDN is low), as shown below. The same reset
pulse is generated after a step-down on the input pin SDN (provided that VDD>VRRT).
Figure 6. Power-on reset timing and limits
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The parameters VRRT and TRESET are fixed by design. At RESET, all the registers are
initialized to their default values. Typical and extreme values are reported in the following
table.
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Operating modes
SPIRIT1
Table 22. POR parameters
Symbol
VRRT
TRESET
Parameter
Min.
Reset startup threshold voltage
Typ.
Max.
0.5
Reset pulse width
0.24
0.65
Unit
V
1.0
ms
Note:
An SRES command is also available which generates an internal RESET of the SPIRIT1.
7.2
Timer usage
Most of the timers are programmable via R/W registers. All timer registers are made up of
two bytes: the first byte is a multiplier factor (prescaler); the second byte is a counter value.
Timer period= PRESCALER x CONTER x Tclk
The available timers and their features are listed in the following table.
Table 23. SPIRIT1 timers description and duration
Note:
No.
Register name
Description
1
RX_TIMEOUT_PRESCALER
2
RX_TIMEOUT_COUNTER
3
LDCR_PRESCALER
4
LDCR_COUNTER
RX operation timeout
Wake-up period
Source
Time
step
Max. time
fCLK/1210
~46µs
~3s
RCO
~29µs
~2s
If the counter register value (prescaler register value) of Rx timeout is 0, it never stops
(infinite timeout), despite the value written in the prescaler register (counter register). It is
not allowed to set LDC_PRESCALER or LDC_COUNTER to 0.
For both timers, the effective number of cycles counted is given by the value + 1 (e.g.
counter=1 and prescaler=1 produces 2 x 2=4 counts, counter=1 and prescaler=2 produces
2 x 3=6 counts, etc.).
The max period of RX TIMEOUT is related to an fCLK of 26 MHz.
7.3
Low duty cycle reload mode
The SPIRIT1 provides an operating mode, low duty cycle reload (LDCR), that allows
operation with very low power consumption, while at the same time keeping an efficient
communication link.The device provides a set of timers to handle low duty cycle reception
efficiently.
The wake up timer is configured, for example to the value Twu, and the device is in SLEEP
for the most of the time, and every Twu it is woken up and set to transmit the content of the
FIFO:
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SPIRIT1
Operating modes
Figure 7. LDCR for Tx
SPEEP for Twu s
TX
GAMS20150209EC-1117
Since the embedded LDCR system automatically manages the transmission strobe, only a
FIFO reload has to be done after the TX done IRQ (or in general, before the next wakeup) in
order to prepare the next Tx.
On the Rx, there is the same behavior, but on this side, there are some important notes in
order to have a reliable link:
1.
At the beginning of the communication the device should always be in continuous Rx
(infinite Rx timeout).
2.
On the first reception the Rx timeout has to be set to be a not infinite value.
3.
Since the embedded LDCR system automatically manages the reception strobe the
only thing to do is a Rx FIFO reading on the RX_DATA_READY interrupt.
So from now on, also the Rx starts the SLEEP/ACTIVE cycles:
Figure 8. LDCR for Rx
RX for an
infinite time
SLEEP for Twu s
RX
RX DONE
(rx timeout
setting)
GAMS20150209EC-1134
The wakeup timer for LDCR mode can be set through the LDC_PRESCALER/COUNTER
registers. This timer is clocked by the 34.7 kHz RC oscillator keeping unused blocks off.
Due to clock mismatches, it would be better to synchronize RX with the incoming packet
every time it occurs in order to ensure the matching between Tx and Rx active slots and
avoid that the Tx transmits out of the Rx active slot.
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SPIRIT1
In fact, even if the Tx and Rx wake up timers are nominally the same, they're measured on
different time bases (considering the RC oscillators of the two devices that are not the same
because of process tolerances).
SPIRIT1 allows doing that in two ways:
–
The value of the wake-up timer can be reloaded during runtime using the
LDCR_RELOAD command with the values written in the
LDC_RELOAD_PRESCALER/COUNTER registers. In doing so, the counting can
be delayed or anticipated.
–
Alternatively, the wake-up timer can be automatically reloaded at the time the
SYNC is received. This option must be enabled on the PROTOCOL register and it
is available only for LDC mode in reception.
It is strongly recommended to use the second way with a reload wakeup time equal to Twutime_to_preamble_and_sync-guard_time in order to wake up the device guard_time ms
before the start of Tx.
The RC oscillator must be calibrated correctly before the LDC mode can be used. Also the
manual calibration setting is recommended to avoid delay during this mode. If some bits of
the IRQ_MASK register are set, the IRQ_STATUS register must be read to allow the access
to the SLEEP state after a reception or transmission phase.
7.3.1
LDC mode with automatically acknowledgement.
The LDC mode can be used together with the automatic acknowledgement (STack packet
format configured). In this case during a single LDC cycle both the operations of reception
and transmission are performed.
If the SPIRIT1 is used as transmitter and the bitfield NACK_TX is RESET (packet's field
NO_ACK = 0), at the end of the transmission phase the SPIRIT1 will go automatically in
reception phase waiting for an ACK packet. At the end of the reception phase it will go in
SLEEP state until the WUT expires.
If the SPIRIT1 is used as receiver with the bitfield AUTO_ACK set and it receives a packet
with the NO_ACK field reset, then the transmission of the ACK packet is automatically
performed. At the end the SPIRIT1 will go in SLEEP until the WUT expires.
7.4
CSMA/CA engine
The CSMA/CA engine is a channel access mechanism based on the rule of sensing the
channel before transmitting. This avoids the simultaneous use of the channel by different
transmitters and increases the probability of correct reception of data being transmitted.
CSMA is an optional feature that can be enabled when performing transmission. Please
note that CSMA must not be enabled when the transceiver is in receive mode. CSMA
cannot be used in conjuction with link layer protocol (see Section 9.7.5) features such as
automatic acknowledgment and automatic retransmission.
When CSMA is enabled, the device performs a clear channel assessment (CCA) before
transmitting any data. In SPIRIT1 implementation, CCA is based on a comparison of the
channel RSSI with a programmable static carrier sense threshold.
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Operating modes
If the CCA finds the channel busy, a backoff procedure may be activated to repeat the CCA
process a certain number of times, until the channel is found to be idle. Each time that CCA
is retried, a counter (NB) is incremented by one, up to the upper limit (NBmax).
When the limit is reached, an NBACKOFF_MAX interrupt request is raised towards the
MCU, to notify that the channel has been repeatedly found busy and so the transmission
has not been performed.
While in backoff, the device stays in SLEEP/READY state in order to reduce power
consumption.
CCA may optionally be persistent, i.e., rather than entering backoff when the channel is
found busy, CCA continues until the channel becomes idle or until the MCU stops it.
The thinking behind using this option is to give the MCU the possibility of managing the CCA
by itself, for instance, with the allocation of a transmission timer: this timer would start when
MCU finishes sending out data to be transmitted, and would end when MCU expects that its
transmission takes place, which would occur after a period of CCA.
The choice of making CCA persistent should come from trading off transmission latency,
under the direct control of the MCU, and power consumption, which would be greater due to
a busy wait in reception mode.
The overall CSMA/CA flowchart is shown in Figure 9, where Tcca and Tlisten are two of the
parameters controlling the clear channel assessment procedure. Design practice
recommends that these parameters average the channel energy over a certain period
expressed as a multiple of the bit period (Tcca) and repeat such measurement several times
covering longer periods (Tlisten). The measurement is performed directly by checking the
carrier sense (CS) generated by the receiver module.
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SPIRIT1
Figure 9. CSMA flowchart
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To avoid any wait synchronization between different channel contenders, which may cause
successive failing CCA operations, the backoff wait time is calculated randomly between 0
and a contention window. The backoff time BO is expressed as a multiple of backoff time
units (BU). The contention window is calculated on the basis of the binary exponential
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SPIRIT1
Operating modes
backoff (BEB) technique, which doubles the size of the window at each backoff retry (stored
in the NB counter):
BO= rand(0,2NB)×BU
The CSMA procedure is then controlled by the following parameters:
SEED_RELOAD: enables/disables the reload of the seed used by the backoff random
generator at the start of each CSMA procedure (at the time when the counter is reset, i.e.
NB=0). If this functionality is not enabled, the seed is automatically generated and updated
by the generator circuit itself.
CSMA_ON: enables/disables the CSMA procedure (11th bit of the PROTOCOL[1] register);
this bit is checked at each packet transmission.
CSMA_PERS_ON: makes the carrier sense persistent, i.e. the channel is continuously
monitored until it becomes free again, skipping the backoff waiting steps (9th bit of the
PROTOCOL[1] register); the MCU can stop the procedure with an SABORT command.
BU_COUNTER_SEED_MSBYTE/LSBYTE: these bytes are used to set the seed of the
pseudo-random number generator when the CSMA cycle starts (CSMA_CONFIG[3:2]
registers), provided that the SEED_RELOAD bit is enabled. Value 0 is not allowed, because
the pseudo-random generator does not work in that case.
BU_PRESCALER[5:0]: prescaler which is used to configure the backoff time unit (b)
BU=BU_PRESCALER in Figure 9 (field of the CSMA_CONFIG[1] register).
CCA_PERIOD[1:0]: code which programs the Tcca time (expressed as a multiple of Tbit
samples) between two successive CS samplings (field of the CSMA_CONFIG[1] register),
as follows:
•
00 64×Tbit
•
01 128×Tbit
•
10 256×Tbit
•
11 512×Tbit.
CCA_LENGTH[3:0]: configuration of Tlisten = [1..15] x Tcca
NBACKOFF_MAX[2:0]: max. number of backoff cycles.
b. Note that the backoff timer is clocked on the 34.7 kHz clock, because, in this case, the SPIRIT1 is in SLEEP
state, in order to reduce power consumption.
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Block description
SPIRIT1
8
Block description
8.1
Power management
The SPIRIT1 integrates a high efficiency step-down converter cascaded with LDOs meant
to supply both analog and digital parts. However, an LDO directly fed by the external battery
provides a controlled voltage to the data interface block.
8.1.1
Switching frequency
The SMPS switching frequency can be provided either by a divider by four or by a
programmable rate multiplier. The divider by four or the rate multiplier is activated when the
EN_RM bit is set both 0 and 1 in the PM_CONFIG[2:0] register bank. When the rate
multiplier is activated, the divider ratio can be programmed by KRM[14:0] word in the
PM_CONFIG[2:0] register bank. In this case, the SMPS switching frequency is given by the
following formula:
KRM ⋅ f CLK
F sw = ----------------------------15
2
The SMPS runs properly when the bits SET_SMPS_VTUNE and SET_SMPS_PLLBW (see
PM_CONFIG[2:0] register bank) are set according to the programmed switching frequency.
Table 24. SMPS configuration settings
8.2
SET_SMPS_PLLBW
SET_SMPS_VTUNE
Switching frequency range
0
0
2.0 MHz - 4.5 MHz
0
1
3.5 MHz - 7.0 MHz
1
0
4.5 MHz - 7.5 MHz
1
1
4.5 MHz - 10 MHz
Power-on-reset (POR)
The power-on-reset circuit generates a reset pulse upon power-up which is used to initialize
the entire digital logic. Power-on-reset senses VBAT voltage.
8.3
Low battery indicator
The battery indicator can provide the user with an indication of the battery voltage level.
There are two blocks to detect battery level:
42/104
•
Brownout with a fixed threshold as defined inTable 19: Battery indicator and low battery
detector
•
Battery level detector with a programmable threshold as defined in Table 19: Battery
indicator and low battery detector.
DocID022758 Rev 8
SPIRIT1
Block description
Both blocks can be optionally activated to provide the MCU with an early warning of
impending power failure. It does not reset the system, but gives the MCU time to prepare for
an orderly power-down and provides hardware protection of data stored in the program
memory, by preventing write instructions being executed.
The low battery indicatorr function is available in any of the SPIRIT1 operation modes. As
this function requires the internal bias circuit operation, the overall current consumption in
STANDBY, SLEEP, and READY modes is increased by 400 µA.
8.4
Voltage reference
This block provides the precise reference voltage needed by the internal circuit.
8.5
Oscillator and RF synthesizer
A crystal connected to XIN and XOUT is used to provide a clock signal to the frequency
synthesizer. The allowed clock signal frequency is either 24, 26, 48, or 52 MHz. As an
alternative, an external clock signal can be used to feed XIN for proper operation. In this
option, XOUT can be left either floating or tied to ground.
Since the digital macro cannot be clocked at that double frequency (48 MHz or 52 MHz), a
divided clock is used in this case.
The digital clock divider is enabled by default and must be kept enabled if the crystal is in
the (48 - 52) MHz range; if the crystal is in the (24 - 26) MHz range, then the divider must be
disabled before starting any TX/RX operation. The safest procedure to disable the divider
without any risk of glitches in the digital clock is to switch into STANDBY mode, hence, set
the bit-field PD_CLKDIV in the XO_RCO_TEST register, and then come back to the READY
state. Also the synthesizer reference signal can be divided by 2, setting the bit-field REFDIV
in the SYNTH_CONFIG register.
The integrated phase locked loop (PLL) is capable to synthesize a wide band of
frequencies, in particular the bands from 150 to 174 MHz, from 300 to 348 MHz, from 387 to
470 MHz, or from 779 to 956 MHz, providing the LO signal for the RX chain and the input
signal for the PA in the TX chain.
Frequency tolerance and startup times depend on the crystal used, although some tuning of
the latter parameter is possible through the GM_CONF field of the ANA_FUNC_CONF
registers.
Table 25. Programmability of trans-conductance at startup
GM_CONF[2:0]
Gm at startup [mS]
000
13.2
001
18.2
010
21.5
011
25.6
100
28.8
101
33.9
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Table 25. Programmability of trans-conductance at startup
GM_CONF[2:0]
Gm at startup [mS]
110
38.5
111
43.0
Depending on the RF frequency and channel spacing, a very high accurate crystal or TCXO
can be required.
The RF synthesizer implements fractional sigma delta architecture to allow fast settling and
narrow channel spacing. It is fully integrated and uses a multi-band VCO to cover the whole
frequency range. All internal calibrations are performed automatically.
The PLL output frequency can be configured by programming the SYNT field of the SYNT3,
SYNT2, SYNT1, and SYNT0 registers and BS field of the SYNT0 register (see
Section 9.5.2). The user must configure these registers according to the effective reference
frequency in use (24 MHz, 26 MHz, 48 MHz, or 52 MHz). In the latter two cases, the user
must enable the frequency divider by 2 for the digital clock, in order to run the digital macro
at a lower frequency. The configuration bit for the digital clock divider is inside the
XO_RCO_TEST register (default case is divider enabled). In addition, the user can also
enable a divider by 2 applied to the reference clock. The configuration bit for the reference
clock divider is inside the SYNTH_CONFIG[1] register. The user must select a 3-bit word in
order to set the charge pump current according to the LO frequency variations, in order to
have a constant loop bandwidth. This can be done by writing the WCP field of the SYNT3
register, according to the following table:
Table 26. CP word look-up
Channel frequency
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WCP [2:0]
145.1
147.1
000
147.1
149.1
001
149.1
151.1
010
151.1
153.2
011
153.2
155.2
100
155.2
157.2
101
157.2
159.2
110
159.2
161.1
111
161.3
163.5
000
163.5
165.7
001
165.7
168.0
010
168.0
170.3
011
170.3
172.5
100
172.5
174.8
101
174.8
177.0
110
177.0
179.3
111
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Block description
Table 26. CP word look-up (continued)
Channel frequency
WCP [2:0]
290.3
294
000
294.3
298.3
001
298.3
302.3
010
302.4
306.4
011
306.4
310.4
100
310.4
314.4
101
314.4
318.4
110
318.4
322.6
111
322.6
327.0
000
327.0
331.4
001
331.4
335.9
010
335.9
340.5
011
340.5
344.9
100
344.9
349.5
101
349.5
353.9
110
353.9
358.5
111
387.0
392.3
000
392.3
397.7
001
397.7
403.0
010
403.0
408.5
011
413.8
419.2
101
419.2
424.6
110
424.6
430.1
111
430.1
436.0
000
436.0
441.9
001
441.9
447.9
010
447.9
454.0
011
454.0
459.9
100
459.9
466.0
101
466.0
471.9
110
471.9
478.0
111
774.0
784.7
000
784.7
795.3
001
795.3
806.0
010
806.0
817.0
011
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Table 26. CP word look-up (continued)
Channel frequency
WCP [2:0]
817.0
827.7
100
827.7
838.3
101
838.3
849.2
110
849.2
860.2
111
860.2
872.0
000
872.0
883.8
001
883.8
895.8
010
908.0
919.8
100
919.8
932.0
101
932.0
943.8
110
943.8
956.0
111
The SPIRIT1 is provided with an automatic and very fast calibration procedure for the
frequency synthesizer. If not disabled, it is performed each time the SYNTH is required to
lock to the programmed RF channel frequency (i.e. from READY to LOCK/TX/RX or from
RX to TX and vice versa). Calibration time is 54 µs.
After completion, the calibration word is used automatically by the SPIRIT1 and is stored in
the RCO_VCO_CALIBR_OUT[1:0] registers.
In order to get the synthesizer locked when the calibration procedure is not enabled, the
correct calibration words to be used must be previously stored in the
RCO_VCO_CALIBR_IN[2:0] registers using VCO_CALIBR_TX and VCO_CALIBR_RX
fields for TX and RX modes respectively.
The advantage of performing an offline calibration is that the LOCK/setting time is roughly
20 µs (using proper VCO_CALIBR_TX/RX register values).
It recommended set the T split time at the longest value (3.47 ns) to facilitate the calibrator
operation, SEL_TSPLIT field of the register SYNTH_CONFIG[0] (register address 0x9F) at
1.
If calibration is enabled, the LOCK/setting time is approximately 80 µs.
8.6
RCO: features and calibration
The SPIRIT1 contains an ultra-low power RC oscillator capable of generating 34.7 kHz with
both 24 MHz and 26 MHz; the RC oscillator frequency is calibrated comparing it against the
digital domain clock fCLK divided by 692 or 750, respectively. The configuration bit, called
24_26MHz_SELECT in the ANA_FUNC_CONF register, contains the information of the
calibrator about the frequency of the crystal under operation. If the digital domain clock is 25
MHz, the setting of the configuration bit 24_26MHz_SELECT will calibrate the low power
RC oscillator according to the following table:
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Block description
Table 27. RC calibrated speed
Digital domain clock
24_26MHz_SELECT
RC calibrated speed
24 MHz
0
34.7 kHz
26 MHz
1
34.7 kHz
25 MHz
0
36.1 kHz
25 MHz
1
33.3 kHz
By default, the calibration is disabled at reset to avoid using an out-of-range reference
frequency (for instance, when the XTAL is 26 MHz and the digital divider is active, in fact, by
default). After the internal clock divider is correctly configured, the user can enable the RCO
calibration in the PROTOCOL[2] register.
The user can replace the internal 34 kHz-signal source with an external one (provided
through a GPIO, Section 10.3). To enable the usage of the external signal, the user must set
the EXT_RCOSC bit in the XO_RCO_CONFIG register. However, the internal calibrator is
not automatically disabled from the EXT_RCOSC bit (the user must reset the
RCO_CALIBRATION bit in the PROTOCOL[2] register, if previously set).
8.6.1
RC oscillator calibration
RC oscillator calibration is enabled when bit RCO_CALIBRATION is set in the
PROTOCOL[2] register (by default the calibration is disabled). The calibration words found
by the calibration algorithm are accessible in the RCO_VCO_CALIBR_OUT[1:0] registers
(fields RWT_OUT[3:0] and RFB_OUT[4:0],).
When the calibration is disabled, the frequency of the RC oscillator is set by a couple of
configuration words, namely RWT_IN[3:0] and RFB_IN[4:0], in the
RCO_VCO_CALIBR_IN[2:0] registers (fields RWT_IN[3:0] and RFB_IN[4:0]). RWT_IN[3:0]
can range from 0 up to 13 (decimal value) affecting the raw value of the frequency, while the
more accurate and fine control is up to RFB_IN[4:0] (ranging from 1 up to 31).
8.7
AGC
The AGC algorithm is designed to keep the signal amplitude within a specific range by
controlling the gain of the RF chain in 6 dB steps, up to a maximum attenuation of 48dB,
starting at a received signal power of about -50dBm.
The signal peak amplitude measured is compared with a low threshold and with a high
threshold. If it is above the high threshold, the attenuation is increased sequentially until the
amplitude goes below the threshold; if the amplitude is below the low threshold, the
attenuation is decreased sequentially until the amplitude goes above the threshold.
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The AGC algorithm is controlled by the following parameters:
•
High threshold: this value sets the digital signal level above which the attenuation is
increased (AGCCTRL1 register, allowed values 0...15).
•
Low threshold: this value sets the digital signal level below which the attenuation is
decreased (AGCCTRL1 register, allowed values 0...15).
•
Measure time: this parameters sets the measurement interval during which the signal
peak is determined (AGCCTRL2 register, allowed values 0...15 ). the actual time is:
12
MEAS_TIME
T AGCmeas = ----------- ⋅ 2
f CLK
ranging from about 0.5µs to about 15ms. In FSK, GFSK and MSK, the measurement
time is normally set to a few µs in order to achieve fast settling of the algorithm. In OOK
and ASK, to avoid an unstable behavior, the measure time must be larger than the
duration of the longest train of '0' symbols expected.
•
8.8
AGC enable: enables the AGC algorithm (AGC_ENABLE: 0>disabled, 1>enabled).
AFC
The SPIRIT1 implements an automatic frequency compensation algorithm to balance
TX/RX crystal frequency inaccuracies. The receiver demodulator estimates the centre of the
received data and compensates the offset between nominal and receiver frequency.
The tracking range of the algorithm is programmable and is a fraction of the receive channel
bandwidth. Frequency offset compensation is supported for 2-FSK, GFSK, and MSK
modulation.
When the relative frequency error between transmitter and receiver is less than half the
modulation bandwidth, the AFC corrects the frequency error without needing extra
bandwidth. When the frequency error exceeds BWmod/2, some extra bandwidth is needed
to assure proper AFC operation under worst-case conditions. The AFC can be disabled if
the TX/RX frequency misalignment is negligible with respect to the receiver bandwidth, for
example, when using a TCXO.
8.9
Symbol timing recovery
The SPIRIT1 supports two different algorithms for the timing recovery. The choice of the
algorithm actually used is controlled by the CLOCK_REC_ALGO_SEL bit of register
FDEV0.
If CLOCK_REC_ALGO_SEL = 0 then a simple first order algorithm is used (shortly referred
to as DLL), if CLOCK_REC_ALGO_SEL = 1 then a second order algorithm is used (shortly
referred to as PLL).
8.9.1
DLL mode
The algorithm is able to control the delay of the local bit timing generator in order to align it
to the received bit period. If there is an error between the actual received bit period and the
nominal one, the relative edges will drift over time and the algorithm will periodically apply a
delay correction to recover.
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Block description
The convergence speed of the loop is controlled by the CLK_REC_P_GAIN parameter in
the CLOCKREC register with a smaller value yielding a faster loop. Allowed values are from
0 to 7.
8.9.2
PLL mode
The PLL algorithm tracks the phase error of the local timing generator relative to received bit
period and controls both frequency and phase to achieve the timing lock. Once that the
relative period error has been estimated and corrected for example during the preamble
phase, then even in presence of long sequences of zeros or ones, the loop is able to keep
lock.
The convergence speed of the loop is controlled by the CLK_REC_P_GAIN and the
CLK_REC_I_GAIN parameters both in the CLOCKREC register. Allowed values are from 0
to 7 for the CLK_REC_P_GAIN and from 0 to 15 for the CLK_REC_I_GAIN.
8.10
Receiver
The SPIRIT1 contains a low-power low-IF receiver which is able to amplify the input signal
and provide it to the ADC with a proper signal to noise ratio. The RF antenna signal is
converted to a differential one by an external balun, which performs an impedance
transformation also. The receiver gain can be programmed to accommodate the ADC input
signal within its dynamic range. After the down-conversion at IF, a first order filter is
implemented to attenuate the out-of-band blockers.
8.11
Transmitter
The SPIRIT1 contains an integrated PA capable of transmitting at output levels between -30
dBm to +11 dBm. The PA is single-ended and has a dedicated pin (TXOUT). The PA output
is ramped up and down to prevent unwanted spectral splatter. In TX mode the PA drives the
signal generated by the frequency synthesizer out to the antenna terminal. The output
power of the PA is programmable via SPI. Delivered power, as well as harmonic content,
depends on the external impedance seen by the PA. To obtain approval on ETSI EN 300
220, it is possible to program TX to send an unmodulated carrier.
The output stage is supplied from the SMPS through an external choke and is loaded with a
LC-type network which has the function of transforming the impedance of the antenna and
filter out the harmonics. The TX and RX pins are tied directly to share the antenna. During
TX, the LNA inputs are internally shorted to ground to allow for the external network
resonance, so minimizing the power loss due to the RX.
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SPIRIT1
Figure 10. Shaping of ASK signal
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8.12
Temperature sensors (TS)
The SPIRIT1 can provide an analog temperature indication as a voltage level, which is
available at the GPIO_0 pin. The voltage level V0 at room temperature (or any other useful
reference temperature) should be acquired and stored by the MCU in order to compensate
for the offset. The relationship between temperature and voltage is the following:
Equation 2
T = 400 ⋅ ( V temp – V 0 ) + ( T 0 + 3.75 )
( °C )
where V0 is the voltage at temperature T0.
Two output modes are available: buffered or not buffered (high output impedance, about
100 kΩ). The latter mode is the default one.
The TS function is available in every operating mode. When enabled, the internal logic
allows the switching on of all the necessary circuitry.
To enable the TS function, the user must perform the following operations:
•
Set to 1 the TS bit in the ANA_FUNC_CONF[0] register
•
Program as “Analog” (00) the GPIO_MODE field in the GPIO0_CONF register (other
fields are neglected)
•
Optionally, enable the buffered mode (the EN_TS_BUFFER bit in the PM_CONFIG[2]
register).
As the TS function requires the internal bias circuit operation, the overall current
consumption in STANDBY, SLEEP, and READY modes is increased by 400 µA.
8.13
AES encryption co-processor
The SPIRIT1 provides data security support as it embeds an advanced encryption standard
(AES) core which implements a cryptographic algorithm in compliance with NIST FIPS 197.
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Transmission and reception
Three registers are available to use the AES engine of SPIRIT1:
•
AES_KEY_IN [15:0]: R/W type register (128-bit), used to provide the key to use
•
AES_DATA_IN [15:0]: R/W type register (128-bit), used to provide the input to the AES
engine
•
AES_DATA_OUT [15:0]: R type register (128-bit), used to retrieve the output of the
AES operation.
The core processes 128-bit data blocks using 128-bit keys.
The AES can be accessed in any of the SPIRIT1 operation modes.
To turn on the AES engine, the AES_ON bit in the ANA_FUNC_CONF[0] register must be
set.
Once the AES engine is on, it processes the operations according to the commands sent.
The SPIRIT1 engine provides 4 different operations:
1.
Encryption using a given encryption key (AES Enc command). In this operation, the
MCU puts the encryption key into the AES_KEY_IN[15:0] register and the data to
encrypt into the AES_DATA_IN[15:0]. The MCU sends the AES Enc command and
when the AES_EOP (end of operation) is issued, the MCU can retrieve the data
encrypted from AES_DATA_OUT[15:0]
2.
Decryption key derivation starting from an encryption key (AES Key command). In this
operation, the MCU puts the encryption key into AES_DATA_IN[15:0]. The MCU sends
the AES Key command and when the AES_EOP (end of operation) is issued, the MCU
can retrieve the decryption key from AES_DATA_OUT[15:0]
3.
Data decryption using a decryption key (AES Dec command). In this operation, the
MCU puts the decryption key into the AES_KEY_IN[15:0] register and the data to
decrypt into AES_DATA_IN[15:0]. The MCU sends the AES Dec command and when
the AES_EOP (end of operation) is issued, the MCU can retrieve the data decrypted
from AES_DATA_OUT[15:0].
4.
Data decryption using a decryption key (AES KeyDec command). In this operation, the
MCU puts the encryption key into the AES_KEY_IN[15:0] register and the data to
decrypt into AES_DATA_IN[15:0]. The MCU sends the AES KeyDec command and
when the AES_EOP (end of operation) is issued, the MCU can retrieve the data
decrypted from AES_DATA_OUT[15:0].
9
Transmission and reception
9.1
PA configuration
The PA output power level can be configured by programming the PA_POWER[8:0] register
bank. The user can store up to eight output levels to provide flexible PA power ramp-up and
ramp-down at the start and end of a frequency modulation transmission as well as ASK
modulation shaping.
The power levels of the ramp are controlled by 7-bit words (PA_LEVEL_x, x=0 − 7),
according to the following table:
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Table 28. PA_level
PA_LEVEL_x
Comment
0
No output power: output stage in high impedance
mode and all circuits switched off.
1
Maximum output power
POUT [dBm]
(170MHz)
11
…
30
0
…
42
-6
…
90
91-127
Minimum level
-34
Reserved
N/A
Incrementing by 1 the PA register value will correspond about to half dB decrement of
output power.
The power ramping is enabled by the PA_RAMP_ENABLE bit. If enabled, the ramp starts
from the level defined by the word PA_LEVEL_0 and stops at the level defined by the word
PA_LEVEL_x, where x is the value of the 3-bit field PA_LEVEL_MAX_INDEX. So, a
maximum of 8 steps can be set up. Figure 11 describes the levels table and shows some
examples.
Each step is held for a time interval defined by the 2-bit field PA_RAMP_STEP_WIDTH. The
step width is expressed in terms of bit period units (Tb/8), maximum value is 3 (which means
4×Tb/8=Tb/2). Therefore the PA ramp may last up to 4 Tb (about 3.3 ms if the bit rate is 1.2
kbit/s).
52/104
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Transmission and reception
Figure 11. Output power ramping configuration
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The set of 8 levels is used to shape the ASK signal. In this case, the modulator works as a
counter that counts up when transmitting a one and down when transmitting a zero. The
counter counts at a rate equal to 8 times the symbol rate (in this case, the field
PA_RAMP_STEP_WIDTH is not used). This counter value is used as an index for the
lookup in the levels table in Figure 11 to associate the relevant POUT value. Therefore, in
order to utilize the whole table, PA_LEVEL_MAX_INDEX should be 7 when ASK is active.
The real shaping of the ASK signal is dependent on the configuration of the PA_LEVEL_x
registers. Figure 11 shows some examples of ASK shaping.
Using the a frequency modulation, the output power is configured by PA_LEVEL_x, with
x=PA_LEVEL_MAX_INDEX.
For OOK modulation, the signal is abruptly switched between two levels only, these are
PA_LEVEL_0 and PA_LEVEL_x, with x=PA_LEVEL_MAX_INDEX.
The 2-bit CWC field in the PA_POWER register bank can be used to tune the internal
capacitive load of the PA (up to 3.6 pF in steps of 1.2 pF) in order to optimize the
performance at different frequencies.
The output power are reported in Table 28: PA_level.
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Transmission and reception
9.2
SPIRIT1
RF channel frequency settings
RF channels can be defined using the CHSPACE and CHNUM registers.
The channel center frequency can be programmed as:
Equation 3
 fXO

fc = fbase + foffset +  15 ⋅ CHSPACE  ⋅ CHNUM
2

This allows the setting of up to 256 channels with a programmable raster. The raster
granularity is about 793 Hz at 26 MHz and becomes about 1587 Hz at 52 MHz.
The actual channel spacing is from 793 Hz to 202342 Hz in 793 Hz steps for the 26 MHz
configuration and from 1587 to 404685 Hz in 1587 Hz steps for the 52 MHz configuration.
The base carrier frequency, i.e. the carrier frequency of channel #0, is controlled by the
SYNT0, SYNT1, SYNT2, and SYNT3 registers according to the following formula:
Equation 4
fbase =
fXO
SYNT
(B * D)
2 18
2
where:
•
fXO is the frequency of the XTAL oscillator (typically 24 MHz, 26 MHz, 48 MHz, or 52
MHz)
•
SYNT is a programmable 26-bit integer.
Equation 5
6 fo r th e high b and (fr o m 7 79 M H z to 9 5 6M H z, BS = 1 )
B=
{
12 fo r th e m id d le b and (3 87 M H z to 4 7 0M Hz, BS = 3)
16 fo r the lo w ba n d ( 3 0 0M H z to 3 48 M Hz ,B S = 4)
3 2 for the very l o w b and (1 69 M Hz,BS = 5)
Equation 6
 1 if REFDIV 0 (internal reference divider is disabled)
D = 
 2 if REFDIV 1 (internal reference divider is enabled)
The offset frequency is a correction term which can be set to compensate the crystal
inaccuracy after e.g. lab calibration.
Equation 7
foffset =
54/104
fXO
218
⋅ FC _ OFFSET
DocID022758 Rev 8
SPIRIT1
Transmission and reception
where:
•
FC_OFFSET is a 12-bit integer (expressed as 2's complement number) set by the
FC_OFFSET[1:0] registers
Furthermore, the selection between VCOH (“high”) and VCOL (“low”) in the frequency
synthesizer according to the band selected and the VCO threshold is required.
If the center frequency is below the frequency threshold for that frequency band, the VCO_L
must be selected by setting the bit 2 VCO_L_SEL field in the SYNTH_CONFIG register.
If the center frequency is above the frequency threshold for that frequency band, VCO_H
must be selected by setting the bit 1 VCO_ H _SEL field in the SYNTH_CONFIG register.
Table 29. Frequency threshold
Frequency threshold for each band (MHz)(1)
Very low band
Low band
Middle band
High band
161281250
322562500
430083334
860166667
1. By default, the VCO_H is selected.
The user must make sure that actual frequency programming is inside the specified
frequency range. The accuracy of the offset is about 99 Hz for the 26 MHz reference and
about 198 Hz for the 52 MHz reference.
9.3
RX timeout management
In SPIRIT1, the RX state is specifically time monitored in order to minimize power
consumption. This is done by a RX timeout approach, which aborts the reception after RX
timeout expiration. The timer used to control RX timeout is controlled by the registers
RX_TIMEOUT_PRESCALER and RX_TIMEOUT_COUNTER . However, to avoid the
reception to be interrupted during a valid packet, a number of options to stop the timeout
timer are available for the user. They are based on the received signal quality indicators
(see Section 9.10 for a full description of them):
•
CS valid
•
SQI valid
•
PQI valid
More specifically, both 'AND' or 'OR' boolean relationships among any of them can be
configured. This is done using the selection bit RX_TIMEOUT_AND_OR_SELECT in
PCKT_FLT_OPTIONS register. To choose which of the quality indicators should be taken
into account in the AND/OR Boolean relationship, the user should use the mask bits
available in the PROTOCOL[2] register.
The full true-table including any logical AND/OR among such conditions is reported in
Table 30.
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SPIRIT1
Table 30. RX timeout stop condition configuration
RX_TIMEOUT_
AND_OR_SELECT
0
CS_TIMEOUT_MASK
0
SQI_TIMEOUT
_MASK
PQI_TIMEOUT_M
ASK
Description
0
The RX timeout never
expires and the reception
ends at the reception of the
packet
0
1
0
0
0
The RX timeout cannot be
stopped. It starts at the RX
state and at the end expires
(default)
X
1
0
0
RSSI above threshold
X
0
1
0
SQI above threshold
X
0
0
1
PQI above threshold
0
1
1
0
Both RSSI AND SQI above
threshold
0
1
0
1
Both RSSI AND PQI above
threshold
0
0
1
1
Both SQI AND PQI above
threshold
0
1
1
1
ALL above threshold
1
1
1
0
RSSI OR SQI above
threshold
1
1
0
1
RSSI OR PQI above
threshold
1
0
1
1
SQI OR PQI above
threshold
1
1
1
1
ANY above threshold
When reception is aborted on timeout expiration, the packet is considered not valid and will
be discarded.
It is responsibility of the user to choose the proper boolean condition that suit its application.
In particular, it is required to include always SQI valid check, to avoid to stay in RX state for
unlimited time, if timeout is stopped but no valid SQI is detected (in such cases, the RX state
can be left using a SABORT command).
It is also important to notice that, in case a packet is received, that the timeout is stopped by
some of the conditions in order to get an RX data ready interrupt, otherwise SPIRIT1 will
wait in RX mode for the RX timeout to expire anyway.
9.4
Intermediate frequency setting
The intermediate frequency (IF) is controlled by the registers IF_OFFSET_ANA and
IF_OFFSET_DIG, and can be set as:
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Transmission and reception
Equation 8
f IF
12
IF_OFFSET_ANA = ROUND ⋅  --------- ⋅ 3 ⋅ 2 – 64
f XO
Equation 9
f IF
12
IF_OFFSET_DIG = ROUND ⋅  ----------- ⋅ 3 ⋅ 2 – 64
 f CLK

where fXO is the XTAL oscillator frequency (24, 25, 26, 48, 50 or 52 MHz) and fCLK is the
digital clock frequency (24, 25 or 26 MHz).
The recommended IF value is about 480 kHz resulting in the following register setting:
Table 31. IF_OFFSET settings
9.5
IF_OFFSET_ANA
IF_OFFSET_DIG
fIF [kHz]
fXO [MHz]
0xB6
0xB6
480.469
24
0xAC
0xAC
480.143
25
0xA3
0xA3
480.306
26
0x3B
0xB6
480.469
48
0x36
0xAC
480.143
50
0x31
0xA3
480.140
52
Modulation scheme
The following modulation formats are supported: 2-FSK, GFSK, MSK, OOK, and ASK. The
actual modulation format used is controlled by the MOD_TYPE field of the MOD0 register:
•
MOD_TYPE =
–
0 (00): 2-FSK
–
1 (01): GFSK
–
2 (10): ASK/OOK
–
3 (11): MSK
In 2-FSK and GFSK modes, the frequency deviation is controlled by the FDEV register
according to the following formula:
Equation 10
FDEV_E – 1
floor ( ( 8 + FDEV_M ) ⋅ 2
)f dev = f xo ------------------------------------------------------------------------------------------18
2
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SPIRIT1
where:
•
fXO is the XTAL oscillator frequency (typically 26 MHz or 52 MHz).
•
FDEV_M is a 3-bit integer ranging from 0 to 7
•
FDEV_E is a 4-bit integer ranging from 0 to 9.
The fdev values obtainable are then:
For fXO = 52 MHz
E/M
0
1
2
3
4
5
6
7
0
793.5
793.5
991.8
991.8
1190.2
1190.2
1388.5
1388.5
1
1586.9
1785.3
1983.6
2182.0
2380.4
2578.7
2777.1
2975.5
2
3173.8
3570.6
3967.3
4364.0
4760.7
5157.5
5554.2
5950.9
3
6347.7
7141.1
7934.6
8728.0
9521.5
10314.9
11108.4
11901.9
4
12695.3
14282.2
15869.1
17456.1
19043.0
20629.9
22216.8
23803.7
5
25390.6
28564.5
31738.3
34912.1
38085.9
41259.8
44433.6
47607.4
6
50781.3
57128.9
63476.6
69824.2
76171.9
82519.5
88867.2
95214.8
7
101562.5
114257.8
126953.1
139648.4
152343.8
165039.1
177734.4
190429.7
8
203125.0
228515.6
253906.3
279296.9
304687.5
330078.1
355468.8
380859.4
9
406250.0
457031.3
507812.5
558593.8
609375.0
660156.3
710937.5
761718.8
For fXO = 26 MHz
E/M
0
1
2
3
4
5
6
7
0
396.7
396.7
495.9
495.9
595.1
595.1
694.3
694.3
1
793.5
892.6
991.8
1091.0
1190.2
1289.4
1388.5
1487.7
2
1586.9
1785.3
1983.6
2182.0
2380.4
2578.7
2777.1
2975.5
3
3173.8
3570.6
3967.3
4364.0
4760.7
5157.5
5554.2
5950.9
4
6347.7
7141.1
7934.6
8728.0
9521.5
10314.9
11108.4
11901.9
5
12695.3
14282.2
15869.1
17456.1
19043.0
20629.9
22216.8
23803.7
6
25390.6
28564.5
31738.3
34912.1
38085.9
41259.8
44433.6
47607.4
7
50781.3
57128.9
63476.6
69824.2
76171.9
82519.5
88867.2
95214.8
8
101562.5
114257.8
126953.1
139648.4
152343.8
165039.1
177734.4
190429.7
9
203125.0
228515.6
253906.3
279296.9
304687.5
330078.1
355468.8
380859.4
With this solution the maximum deviation for the 26 MHz case is limited to about 355 kHz,
but this is still acceptable since the maximum useful deviation is about 125 kHz (MSK @
500 kbps).
In GFSK mode the Gaussian filter BT product can be set to 1 or 0.5 by the field BT_SEL of
the MOD0 register.
In MSK mode, the frequency deviation is automatically set to ¼ of the data rate and the
content of the FDEV register is ignored.
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The calculation done inside the modem assumes that the digital clock is equal to the
synthesizer reference. Hence, in the 52-MHz case the MSK can actually be configured by
setting the frequency deviation to ¼ of the data rate through the FDEV registers as for
normal 2-FSK. The same is true for GMSK mode, which can be configured by setting the
frequency deviation to ¼ of the data rate through the FDEV registers as for normal GFSK
with Gaussian filter BT equal to 1 or 0.5.
OOK and ASK
If MOD_TYPE = 2 and power ramping is enabled, then ASK is used; otherwise, if
MOD_TYPE = 2 and power ramping is disabled, then OOK is used.
When OOK is selected, a bit '1' is transmitted with the power specified by
PA_POWER[PA_LEVEL_MAX_INDEX], a bit '0' is transmitted with the power specified by
PA_POWER[0](normally set to PA off).
When ASK is selected, a bit '1' is transmitted with a power ramp increasing from
PA_POWER[0] to PA_POWER[PA_LEVEL_MAX_INDEX], a bit '0' is transmitted with a
power ramp decreasing from PA_POWER[PA_LEVEL_MAX_INDEX] to PA_POWER[0].
The duration of each power step is 1/8 of the symbol time.
If more '1's are transmitted consecutively, the PA power remains at
PA_POWER[PA_LEVEL_MAX_INDEX] for all '1's following the first one; If more '0's are
transmitted consecutively, the PA power remains at PA_POWER[0] for all '0's following the
first one.
CW mode
For test and measurement purposes the device can be programmed to generate a
continuous wave carrier without any modulation by setting the CW field of the MOD0
register. In transmission, a TXSOURCE like PN9 should be configured to keep the
transmitter in TX state for an undefined period of time. In reception, this mode can be also
chosen to analyze the RX performance; in this case an infinite RX timeout should be
configured to keep the SPIRIT1 in RX state.
9.5.1
Data rate
The data rate is controlled by the MOD0 and MOD1 registers according to the following
formula:
Equation 11
DATARATE_E
( 256 + DATA_RATE_M ) ⋅ 2
DataRate = f clk ⋅ -----------------------------------------------------------------------------------------------------28
2
where:
•
DATARATE_M is an 8-bit integer ranging from 0 to 255
•
DATARATE_E is a 4-bit integer ranging from 0 to 15
•
fclk is the digital clock frequency (typically 26 MHz).
The minimum data rate at fclk = 26 MHz is about 25 Hz; the maximum data rate is about 1.6
MHz. Be advised that performance for such values is not guaranteed.
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9.5.2
SPIRIT1
RX channel bandwidth
The bandwidth of the channel filter is controlled by the CHFLT_M and CHFLT_E fields of the
CHFLT register according to tables below. The actual filter bandwidth for any digital clock
frequency can be obtained by multiplying the values in the tables below by the factor
fclk/26000000.
Table 32. CHFLT_M and CHFLT_E value for channel filter bandwidth (in kHz, for fclk = 24 MHz)
E=0
E=1
E=2
E=3
E=4
E=5
E=6
E=7
E=8
E=9
M=0
738.6
416.2
207.4
103.7
51.8
25.8
12.9
6.5
3.2
1.7
M=1
733.9
393.1
196.1
98.0
48.9
24.5
12.3
6.1
3.0
1.6
M=2
709.3
372.2
185.6
92.8
46.3
23.2
11.6
5.8
2.9
1.5
M=3
680.1
351.5
175.4
87.7
43.8
21.9
11.0
5.4
2.8
1.4
M=4
650.9
334.2
166.8
83.4
41.6
20.9
10.4
5.2
2.6
1.3
M=5
619.3
315.4
157.5
78.7
39.3
19.7
9.8
4.9
2.5
1.2
M=6
592.9
300.4
149.9
75.0
37.5
18.7
9.3
4.7
2.3
1.2
M=7
541.6
271.8
135.8
67.8
33.9
17.0
8.5
4.2
2.1
1.1
M=8
499.8
249.5
124.6
62.3
31.1
15.6
7.8
3.9
1.9
1.0
Table 33. CHFLT_M and CHFLT_E value for channel filter bandwidth (in kHz, for fclk = 26 MHz)
E=0
E=1
E=2
E=3
E=4
E=5
E=6
E=7
E=8
E=9
M=0
800.1
450.9
224.7
112.3
56.1
28.0
14.0
7.0
3.5
1.8
M=1
795.1
425.9
212.4
106.2
53.0
26.5
13.3
6.6
3.3
1.7
M=2
768.4
403.2
201.1
100.5
50.2
25.1
12.6
6.3
3.1
1.6
M=3
736.8
380.8
190.0
95.0
47.4
23.7
11.9
5.9
3.0
1.5
M=4
705.1
362.1
180.7
90.3
45.1
22.6
11.3
5.6
2.8
1.4
M=5
670.9
341.7
170.6
85.3
42.6
21.3
10.6
5.3
2.7
1.3
M=6
642.3
325.4
162.4
81.2
40.6
20.3
10.1
5.1
2.5
1.3
M=7
586.7
294.5
147.1
73.5
36.7
18.4
9.2
4.6
2.3
1.2
M=8
541.4
270.3
135.0
67.5
33.7
16.9
8.4
4.2
2.1
1.1
Although the maximum TX signal BW should not exceed 750 kHz, the bandwidth of the
channel select filter in the receiver may need some extra bandwidth to cope with tolerances
in transmit and receive frequencies which depend on the tolerances of the used crystals.
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Transmission and reception
9.6
Data coding and integrity check process
9.6.1
FEC
The device provides hardware support for error correction and detection.
Error correction can be either enabled or disabled according to link reliability and power
consumption needs. Convolutional coding with a rate=½ and k=4 is applied on the payload
and CRC before transmission (poly [13,17]). On the receiver side, error correction is
performed using soft Viterbi decoding.
To further improve error correction performance, a data interleaver is used when
convolutional coding is enabled. Data interleaving/de-interleaving is performed using a 4x4bit matrix interleaver.
To fill the entire matrix, at least 2 bytes of data payload are required (16 cells). In the
interleaver matrix, the encoded data bits are written along the rows and the sequence to
send to the modulator is obtained by reading the matrix elements along the columns of the
matrix. Consequently, in the de-interleaver, the received data from the demodulator are
written into the matrix along the columns, and sent to the FEC decoder reading them from
the rows of the de-interleaving matrix. Due to the size of the matrix, the overall data
transmitted must be an exact integer multiple of two, to fill the rows and columns of the
matrix. If necessary, the framer is able to add automatically extra bytes at the end of the
packet, so the number of bytes is an number.
FEC and interleaving are enabled/disabled together.
To enable FEC/INTERL, the field FEC_EN of PCKTCTRL1 must be set to ‘1’. When
FEC/INTERL is enabled, the number of transmitted bits is roughly doubled, hence the on-air
packet duration in time is roughly doubled as well. The data rate specified in Section 9.5.1
always applies to the on-air transmitted data.
A termination byte is automatically appended to set the encoder to the 0-state at the end of
the packet.
9.6.2
CRC
Error detection is implemented by means of cyclic redundancy check codes.
The length of the checksum is programmable to 8, 16, or 24 bits.
The CRC can be added at the end of the packet by the field CRC_MODE of the register
PCKCTRL1.
The following standard CRC polynomials can be selected:
•
CRC mode = 1, 8 bits: the poly is (0x07) X8+X2+X+1
•
CRC mode = 2, 16 bits: the poly is (0x8005) X16+X15+X2+1
•
CRC mode = 3, 16 bits: the poly is (0x1021) X16+X12+X5+1
•
CRC mode = 4, 24 bits: the poly is (0x864CFB)
X24+X23+X18+X17+X14+X11+X10+X7+X6+X5+X4+X3+X+1
•
CRC is calculated over all fields excluding preamble and SYNC word.
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9.6.3
SPIRIT1
Data whitening
To prevent short repeating sequences (e.g., runs of 0's or 1's) that create spectral lines,
which may complicate symbol tracking at the receiver or interferer with other transmissions,
the device implements a data whitening feature. Data whitening can optionally be enabled
by setting the filed WHIT_EN of the PCKTCTRL1 register to '1'. Data whitening is
implemented by a maximum length LFSR generating a pseudo-random binary sequence
used to XOR data before entering the encoding chain. The length of the LSFR is set to 9
bits. The pseudo-random sequence is initialized to all 1's.
Data whitening, if enabled, is applied on all fields excluding the preamble and the SYNC
words.
At the receiver end, the data are XOR-ed with the same pseudo-random sequence.
Whitening is applied according to the following LFSR implementation:
Figure 12. LFSR block diagram
8
7
6
5
4
3
2
1
Tx
0
Tout
AM03940v1
It is recommended to always enable data whitening.
9.6.4
Data padding
If FEC is enabled then the total length of payload and CRC must be an even number (in
order to completely fill up the interleaver). If not, a proper filling byte is automatically inserted
in transmission and removed by the receiver. The total packet length is affected, and it is
configured automatically enabling the FEC.
9.7
Packet handler engine
Before on-the-air transmission, raw data is properly cast into a packet structure. The
SPIRIT1 offers a highly flexible and fully programmable packet; the structure of the packet,
the number, the type, and the dimension of the fields inside the packet depend on one of the
possible configuration settings. Through a suitable register the user can choose the packet
configuration from three options: STack, WM-Bus, and Basic.
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The current packet format is set by the PCK_FRMT field of the PCKTCTRL3 register. In
particular:
•
0 Basic packet format
•
2 MBUS packet format
•
3 STack packet format.
The general packet parameters which can be set by the user are listed and described
hereafter. Some particular restrictions are possible depending on the selected packet
format.
9.7.1
STack packet
1-32
1-4
0-16 bit
Preambl
e
Sync
Length
1
1
Dest.
Source
address address
0-4
Control
2 bit
1 bit
Seq. No. NO_ACK
0-65535
0-3
Payload
CRC
Preamble (programmable field): the length of the preamble is programmable from 1 to 32
bytes by the PREAMBLE_LENGTH field of the PCKTCTRL2 register. Each preamble byte is
a '10101010' binary sequence.
Sync (programmable field): the length of the synchronization field is programmable (from 1
to 4 bytes) through dedicated registers. The SYNC word is programmable through registers
SYNC1, SYNC2, SYNC3, and SYNC4. If the programmed sync length is 1 then only the
SYNC1 word is transmitted; if the programmed sync length is 2 then only SYNC1 and
SYNC2 words are transmitted and so on.
Length (programmable/optional field): the packet length field is an optional field that is
defined as the cumulative length of Address (2 bytes always), Control, and Payload fields. It
is possible to support fixed and variable packet length. In fixed mode, the field length is not
used.
Destination address (programmable field): When the destination address filtering is
enabled in the receiver, the packet handler engine compares the destination address field of
the packet received with the value of register TX_SOURCE_ADDR. If broadcast address
and/or multicast address filtering are enabled the packet handler engine compares the
destination address with the programmed broadcast and/or multicast address.
Source address (programmable field): is filled with the value of register
TX_SOURCE_ADDR. When source address filtering is enabled in the receiver, the packet
handler engine compares the source address received with the programmed source
address reference using the source mask address programmed.
The field ADDRESS_LEN of the PCKTCTRL4 register must be set always to 2.
Control (programmable/optional field): is programmable from 0 to 4 bytes through the
CONTROL_LEN field of the PCKTCTRL4 register. Control fields of the packet can be set
using the TX_CTRL_FIELD[3:0] register.
Sequence number (programmable field): is a 2-bit field and contains the sequence number
of the transmitted packet. It is incremented automatically every time a new packet is
transmitted. It can be re-loaded with the value in the TX_SEQ_NUM_RELOAD[1:0] field of
the PROTOCOL[2] register, by using the SEQUENCE_UPDATE command.
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NO_ACK (programmable field): 1 means for the receiver that the packet is not to be autoacknowledged. It is programmed by the bit field NACK_TX of the register PROTOCOL[2]. It
is important set to 0 this bit field in any other packet format.
Payload (programmable/optional field): the device supports both fixed and variable payload
length transmission from 0 to 65535 bytes.
On the transmitter, the payload length is always set as: PCKTLEN1 × 256 + PCKTLEN0.
On the receiver, if the field FIX_VAR_LEN of the PCKTCTRL2 register is set to 1, the
payload length is directly extracted from the received packet itself; if FIX_VAR_LEN is set to
0, the payload length is controlled by the PCKTLEN0 and PCKTLEN1 registers as the
transmitter.
In variable length mode, the width of the binary field transmitted, where the actual length of
payload is written, can be configured through the field LEN_WIDTH of the PCKTCTRL3
register according to the maximum length expected in the specific application.
Example 1
•
If the variable payload length is from 0 to 31 bytes, then LEN_WIDTH = 5
•
If the variable payload length is from 0 to 255 bytes, then LEN_WIDTH = 8
•
If the variable payload length is from 0 to 65535 bytes, then LEN_WIDTH = 16.
CRC (programmable/optional field): There are different polynomials CRC: 8 bits, 16 bits (2
polynomials are available) and 24 bits. When CRC automatic filtering is enabled, the
received packet is discarded automatically when CRC check fails.
9.7.2
Wireless M-Bus packet (W M-BUS, EN13757-4)
The WM-BUS packet structure is shown in the figure below (refer to EN13757 for details
about sub-mode specific radio setting).
Bytes nx(01)
Preamble
nx(01)
Sync
st
1 block
2nd
block
Opt. blocks
Postamble
Manchester or 3 out of 6 encoding
The preamble consists of a number of chip sequences '01' whose length depends on the
chosen sub-mode according to EN13757-4. The length can be programmed using the
MBUS_PRMBL_CTRL, from a minimum to a maximum dictated from the standard
specification.
1st block, 2nd block, and optional blocks: can be defined by the user. The packet handler
engine uses the Manchester or the “3 out of 6” encoding for all the blocks according to the
defined sub-mode.
The postamble consists of a number of chip sequences '01' whose length depends on the
chosen sub-mode according to EN13757-4. The length can be programmed using the
MBUS_PSTMBL_CTRL, from a minimum to a maximum dictated from the standard
specification.
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Transmission and reception
The sub-mode can be chosen setting the MBUS_SUBMODE[2:0] field of the MBUS_CTRL
register. There are 5 possible cases:
•
•
•
•
•
9.7.3
Submode S1, S2 (long header) (MBUS_SUBMODE=0):
–
Header length = MBUS_PRMBL_CTRL + 279 (in '01' bit pairs)
–
Sync word = 0x7696 (length 18 bits)
Submode S1-m, S2, T2 (other to meter) (MBUS_SUBMODE =1):
–
Header length = MBUS_PRMBL_CTRL + 15 (in '01' bit pairs)
–
Sync word = 0x7696 (length 18 bits)
Submode T1, T2 (meter to other) (MBUS_SUBMODE =3):
–
Header length = MBUS_PRMBL_CTRL + 19 (in '01' bit pairs)
–
Sync word = 0x3D (length 10 bits)
Submode R2, short header (MBUS_SUBMODE =5):
–
Header length = MBUS_PRMBL_CTRL + 39 (in '01' bit pairs)
–
Sync word = 0x7696 (length 18 bits).
Submode N1, N2, short header:
–
Header length = 8 (in '01' bit pairs)
–
Sync word = 0xF68D (length 18 bits).
Basic packet
1-32
1-4
0-16 bit
0-1
0-4
0-65535
0-3
Preamble
Sync
Length
Address
Control
Payload
CRC
Preamble (programmable field): the length of the preamble is programmable from 1 to 32
bytes by the PREAMBLE_LENGTH field of the PCKTCTRL2 register. Each preamble byte is
a '10101010' binary sequence.
Sync (programmable field): the length of the synchronization field is programmable (from 1
to 4 bytes) through dedicated registers. The SYNC word is programmable through registers
SYNC1, SYNC2, SYNC3, and SYNC4. If the programmed sync length is 1, then only SYNC
word is transmitted; if the programmed sync length is 2 then only SYNC1 and SYNC2 words
are transmitted and so on.
Length (programmable/optional field): the packet length field is an optional field that is
defined as the cumulative length of Address, Control, and Payload fields. It is possible to
support fixed and variable packet length. In fixed mode, the field length is not used.
Destination address (programmable/optional field): when the destination address filtering
is enabled in the receiver, the packet handler engine compares the destination address field
of the packet received with the value of register TX_SOURCE_ADDR. If broadcast address
and/or multicast address filtering are enabled, the packet handler engine compares the
destination address with the programmed broadcast and/or multicast address.
Control (programmable/optional field): is programmable from 0 to 4 bytes through the
CONTROL_LEN field of the PCKTCTRL4 register. Control fields of the packet can be set
using the TX_CTRL_FIELD[3:0] register.
Payload (programmable/optional field): the device supports both fixed and variable payload
length transmission from 0 to 65535 bytes.
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On the transmitter, the payload length is always set as: PCKTLEN1 × 256 + PCKTLEN0.
On the receiver, if the field FIX_VAR_LEN of PCKTCTRL2 register is set to 1, the payload
length is directly extracted from the received packet itself; if FIX_VAR_LEN is set to 0, the
payload length is controlled by the PCKTLEN0 and PCKTLEN1 registers as the transmitter.
Furthermore, in variable length mode, the width of the binary field transmitted, where the
actual length of payload is written, must be configured through the field LEN_WIDTH of the
PCKTCTRL3 register according to the maximum length expected in the specific application.
Example 1
•
If the variable payload length is from 0 to 31 bytes, then LEN_WIDTH = 5
•
If the variable payload length is from 0 to 255 bytes, then LEN_WIDTH = 8
•
If the variable payload length is from 0 to 65535 bytes, then LEN_WIDTH = 16.
CRC (programmable/optional field): There are different polynomials CRC: 8 bits, 16 bits (2
polynomials are available) and 24 bits. When the CRC automatic filtering is enabled, the
received packet is discarded automatically when the CRC check fails.
9.7.4
Automatic packet filtering
The following filtering criteria to automatically reject a received packet are supported:
•
CRC filtering
•
Destination address filtering
•
Source address filtering
•
Control field filtering.
Packet filtering is enabled by the AUTO_PCKT_FLT field of the PROTOCOL register and
the filtering criteria can be controlled by the PCK_FLT_OPT and PCK_FLT_GOALS
registers.
Each filtering option works on the correct packet format according to Table 34.
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•
CRC: the received packet is discarded if CRC is not passed. To enable this automatic
filtering feature the bit field CRC_CHECK of the PCK_FLT_OPT register must be set.
•
Destination address: this automatic filtering feature works on my address, broadcast
address and/or multicast address of the receiver.
–
Destination vs. my address: the received packet is discarded if the destination
address received does not match the programmed my address of the receiver. My
address can be programmed for the receiver in the TX_SOURCE_ADDR register.
To enable this automatic filtering option the bitfield DEST_VS_SOURCE_ADDR of
the PCKT_FLT_OPTIONS register must be set.
–
Destination vs. broadcast address: the received packet is discarded if the
destination address received does not match the programmed broadcast address
of the receiver. The broadcast address can be programmed for the receiver in the
BROADCAST register. To enable this automatic filtering option the bitfield
DEST_VS_BROADCAST_ADDR of the PCKT_FLT_OPTIONS register must be
set.
–
Destination vs. multicast address: the received packet is discarded if the
destination address received does not match the programmed multicast address
of the receiver. The multicast address can be programmed for the receiver in the
MULTICAST register. To enable this automatic filtering option the bitfield
DocID022758 Rev 8
SPIRIT1
Transmission and reception
DEST_VS_MULTICAST_ADDR of the PCKT_FLT_OPTIONS register must be
set.
More than one automatic filtering option can be enabled at the same time.
Source address: the received packet is discarded if the source address received does not
match the programmed source address reference through the source mask address (the
reference value used for the comparison is the reference one in AND bitwise with the source
mask). The source address reference can be programmed for the receiver in the
RX_SOURCE_ADDR register and the source address mask in the RX_SOURCE_MASK
register. To enable this automatic filtering option the bitfield SOURCE_FILTERING of the
PCKT_FLT_OPTIONS register must be set.
Control: the received packet is discarded if the control field received does not match the
programmed control reference through the control mask (the reference value used for the
comparison is the reference one in AND bitwise with the control mask). The control
reference can be programmed for the receiver in the CONTROLx_FIELD registers and the
control field mask in the CONTROLx_MASK registers. To enable this automatic filtering
option the bitfield CONTROL_FILTERING of the PCKT_FLT_OPTIONS register must be
set.
Table 34. Packet configuration
STack
MBUS
Basic
Destination address filtering
Optional
No
Optional
Broadcast and multicast
addressing
Optional
No
Optional
Source address filtering
Optional
No
No
Custom filtering
Optional
No
Optional
CRC filtering
Optional
No
Optional
When a filtering mechanism is enabled the packet is signaled to the MCU only if the check is
positive, otherwise the packet is automatically discarded.
9.7.5
Link layer protocol
SPIRIT1 has an embedded auto-ACK and auto-retransmission available through the STack
packet format.
Automatic acknowledgment
Automatic acknowledgment is enabled on the receiver by setting the bitfield AUTO_ACK of
the PROTOCOL register. In this way, after the receiver receives a packet with success, it
sends an ACK packet only if the NO_ACK bit of the received packet is 1. This gives an
opportunity for the transmitter to tell the receiver if the packet sent must be acknowledged or
not. The ACK request can be put in the packet (NO_ACK packet's bitfield at 1) by setting the
NACK_TX field of the PROTOCOL[2] register.
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If the ACK request is ON (NO_ACK packet's bitfield at 1), the transmitter stays in RX state to
receive an ACK packet until the RX timeout, programmed with the
RX_TIMEOUT_PRESCALER and RX_TIMEOUT_COUNTER, expires.
If the transmitter does not receive any ACK packet when it must, the packet transmitted is
considered lost, and the TX_DATA_SENT in the IRQ_STATUS register remains at 0.
Automatic acknowledgment with piggybacking
The receiver can fill the ACK packet with data. To do so, the receiver must fill the TX FIFO
with the payload it must transmit and the bitfield PIGGYBACKING of PROTOCOL[1] register
must be set.
With the automatic acknowledgement enabled, the TX strobe is not supported and must not
be sent.
Automatic retransmission
If the transmitter does not receive the ACK packet, it can be configured to do another
transmission. This operation can be repeated up to 15 times. To configure how many times
this operation must be performed, the field NMAX_RETX of the PROTOCOL[2] register is
used.
With the automatic retransmission enabled the RX strobe is not supported and must not be
sent.
Using the automatic retransmission the payload must be loaded into the TX FIFO register
with a single write FIFO operation in READY state.
9.8
Data modes
Direct modes are primarily intended to completely bypass all the framer/deframer
operations, in order to give the user maximum flexibility in the choice of frame formats,
controlled by the field TXSOURCE of the PCKTCTRL1 register. In particular:
TXSOURCE =
•
0 - normal modes
•
1 - direct through FIFO: the packet is written in TX FIFO. The user builds the packet
according to his need including preamble, payload and so on. The data are transmitted
without any processing.
•
2 - direct through GPIO: the packet bits are continuously read from one of the GPIO
pins, properly configured, and transmitted without any processing. To allow the
synchronization of an external data source, a data clock signal is also provided on one
of the GPIO pins. Data are sampled by the device on the rising edge of such clock
signal; it is the responsibility of the external data source to provide a stable input at this
edge.
•
3 - PN9 mode: a pseudo-random binary sequence is generated internally. This mode is
provided for test purposes only.
To improve flexibility, the entire packet related functions can be bypassed and the device
can operate in one of the following direct modes, controlled by the field RXMODE of
PCKTCTRL3. In particular:
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Transmission and reception
RXMODE =
9.9
•
0 - normal modes
•
1 - direct through FIFO: the packet bytes are continuously received and written to the
RX FIFO without any processing. It is the responsibility of the microcontroller to avoid
any overflow conditions on the RX FIFO.
•
2 - direct through GPIO: the packet bits are continuously written to one of the GPIO
pins without any processing. To allow the synchronization of an external data sink, a
data clock signal is also provided on one of the GPIO pins. Data are updated by the
device on the falling edge of such clock signal so the MCU must read it during falling
edge of CLK.
Data FIFO
In the SPIRIT1 there are two data FIFOs, a TX FIFO for data to be transmitted and an RX
FIFO for the received data.
The length of both FIFOs is 96 bytes.
The SPI interface is used to read from the RX FIFO and write to the TX FIFO (see
Figure 13) starting from the address 0xFF.
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Figure 13. Threshold of the linear FIFO
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The FIFO has two programmable thresholds: FIFO almost full and FIFO almost empty.
The FIFO almost full event occurs when the data crosses the threshold from below to
above. The TX FIFO almost empty threshold can be configured using the field TXAETHR in
the FIFO_CONFIG[0] register. The RX FIFO almost empty threshold can be configured
using the field RXAETHR in the FIFO_CONFIG[2] register.
The FIFO almost empty event occurs when the data crosses the threshold from above to
below. The TX FIFO almost full threshold can be configured using the field TXAFTHR in the
FIFO_CONFIG[1] register. The RX FIFO almost full threshold can be configured using the
field RXAFTHR in the FIFO_CONFIG[3] register.
Another event occurs when the FIFO goes into overflow or underflow.
The overflow happens when the data in the FIFO are more than 96 bytes. The underflow
happens when the SPIRIT1 accesses the FIFO locations to read data, but there is no data
present.
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Transmission and reception
For example:
•
If it reads from the RX FIFO more data than the actual number of bytes in it, the RX
FIFO underflow/overflow error occurs for an underflow event.
•
If the SPIRIT1 receives a lot of data to fill the RX FIFO and exceeds the 96 bytes limit,
an RX FIFO underflow/overflow error occurs for an overflow event.
•
If it sends more data than the actual number of bytes in the TX FIFO, the TX FIFO
underflow/overflow error occurs for an underflow event.
•
If it writes more than 96 bytes in the TX FIFO, a TX FIFO underflow/overflow error
occurs for an overflow event.
An easy way to clean the FIFOs is to use the flush commands: FLUSHTXFIFO for the TX
FIFO and FLUSHRXFIFO for the RX FIFO.
The write TX FIFO operation needs an extra SPI transaction to write correctly the last byte
into the TX FIFO. Usually, this last SPI transaction is generated from the TX command sent
to transmit the data, otherwise a dummy SPI transaction must be done.
Using the auto-retransmission feature of the SPIRIT1 (packet format STack), if the packet is
more than 96 bytes, the packet must be reloaded into the TX FIFO by the MCU. However, if
the payload is 96 bytes or less, the SPIRIT1 handles the payload and it is not necessary to
reload the data into the TX FIFO at each retransmission.
•
9.10
In addition, if the transmitter does not receive the ACK packet, the payload remains in
the TX FIFO. The user can decide to clean the TX FIFO or re-send the data again. If
the payload is more than 96 bytes, only the last part of the payload that fits the TX FIFO
remains in it.
Receiver quality indicators
The following quality indicators are associated to the received signal:
9.10.1
•
Received signal strength indicator (RSSI)
•
Link quality indicator (LQI)
•
Preamble quality indicator (PQI)
•
Synchronization quality indicator (SQI).
RSSI
The received signal strength indicator (RSSI) is a measurement of the received signal
power at the antenna measured in the channel filter bandwidth.
RSSI reading is available after the reception of a packet in the RSSI_LEVEL register. The
measured power is reported in steps of 0.5 dB according to the following formula:
RSSI = RSSI_LEVEL/2 – 130
The RSSI value is updated in the RSSI_LEVEL register when the SPIRIT1 exits from the
RX state by SABORT command, RX timeout expiration or at the SYNC word detected
event.
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104
Transmission and reception
9.10.2
SPIRIT1
Carrier sense
The carrier sense functionality can be used to detect if any signal is being received, the
detection is based on the measured RSSI value. There are 2 operational modes for carrier
sensing: static and dynamic.
When static carrier sensing is used (CS_MODE = 0), the carrier sense signal is asserted
when the measured RSSI is above the value specified in the RSSI_TH register and is deasserted when the RSSI falls 3 dB below the same threshold.
When dynamic carrier sense is used (CS_MODE = 1, 2, 3), the carrier sense signal is
asserted if the signal is above the threshold and a fast power increase of 6, 12, or 18 dB is
detected; it is de-asserted if a power fall of the same amplitude is detected.
The carrier sense signal is also used internally for the demodulator to start the AFC and
symbol timing recovery algorithms and for the CSMA procedure (for this use it should be set
to CS_MODE = 0).
The carrier sense function is controlled by the following parameters:
RSSI threshold:When the RSSI threshold is exceeded, the AFC and the symbol timing
recovery algorithm start to work with the stream of data. To maximize the sensitivity, the
RSSI threshold should be set around 3 dB below the expected sensitivity level. The
RSSI_TH register and the effective RSSI threshold value are linked by the following formula:
RSSI_TH = 2 ⋅ ( RSSI_threshold_dBm + 130 )
CS mode: this parameter controls the carrier sense operational modes (RSSI_FLT register,
allowed values 0...3):
9.10.3
•
CS_MODE = 0 static carrier sensing
•
CS_MODE = 1 dynamic carrier sensing with 6 dB dynamic threshold
•
CS_MODE = 2 dynamic carrier sensing with 12 dB dynamic threshold
•
CS_MODE = 3 dynamic carrier sensing with 18 dB dynamic threshold.
LQI
The link quality indicator is a 4-bit value available through the LINK_QUALIF[0] register. Its
value depends on the noise power on the demodulated signal. The lower the value, the
noisier the signal. Be aware that comparing LQI values measured with different modulation
formats or data rate may lead to inconsistent results.
9.10.4
PQI
The preamble quality indicator (PQI) is intended to provide a measurement of the reliability
of the preamble detection phase.
This indicator counts the number of consecutive bit inversions in the received data stream.
The PQI ranges from 0 to 255. It is increased by 1 every time a bit inversion occurs, while it
is decreased by 4 every time a bit repetition occurs.
It is possible to set a preamble quality threshold in such a way that, if PQI is below the
threshold, the packet demodulation is automatically aborted at/after a timeout after the start
of RX.
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DocID022758 Rev 8
SPIRIT1
Transmission and reception
If the preamble quality indicator check is enabled (field PQI_EN of the QI register set to '1'),
the running peak PQI is compared to a threshold value and the preamble valid IRQ is
asserted as soon as the threshold is passed. The preamble quality threshold is 4×PQI_TH
(PQI_TH = 0...15).
9.10.5
SQI
The synchronization quality indicator (SQI) is a measurement of the best correlation
between the received SYNC word and the expected one. The value representing a perfect
match is 8×SYNC_LENGTH.
This indicator is calculated as the peak cross-correlation between the received data stream
and the expected SYNC word.
It is possible to set a synchronization quality threshold in such a way that, if SQI is below the
threshold, the packet demodulation is automatically aborted.
If the synchronization quality indicator check is enabled (field SQI_EN of the QI register set
to '1'), the running peak SQI is compared to a threshold value and the sync valid IRQ is
asserted as soon as the threshold is passed. The sync quality threshold is equal to 8 ×
SYNC_LEN - 2xSQI_TH with SQI_TH = 0..3. When SQI_TH is 0, a perfect match is
required; when SQI_TH = 1, 2, 3 then 1, 2, or 3-bit errors are respectively accepted.
It is recommended to always enable the SQI check.
RX timeout mechanism
In order to reduce power consumption, a few automatic RX timeout modes are supported.
RX timeout applies both to normal receive mode and to the LDCR mode.
Infinite timeout: in this mode RX is stopped when the packet ends or the SABORT command
strobe is issued (default).
Carrier sense timeout: RX is aborted if the RSSI never exceeds a programmed threshold
within RX timeout.
SQI timeout: in this mode RX is aborted if the synchronization quality indicator (SQI) never
exceeds a programmed threshold within RX timeout.
PQI timeout: in this mode RX is aborted if the preamble quality indicator (PQI) never
exceeds a programmed threshold within RX timeout.
The value of RX timeout can be programmed ranging from ~1 µs to ~3 sec.
9.11
Antenna diversity
The device implements a switching based antenna diversity algorithm. The switching
decision is based on a comparison between the received power level on antenna 1 and
antenna 2 during the preamble reception.
The antenna switching function allows to control an external switch in order to select the
antenna providing the highest measured RSSI.
When antenna switching is enabled, the two antennas are repeatedly switched during the
reception of the preamble of each packet, until the carrier sense threshold is reached(c)
(static carrier sense mode must be used). From this point on, the antenna with the highest
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Transmission and reception
SPIRIT1
power is selected and switching is frozen. The switch control signal is available on GPIO
and in the MC_STATE[1] register.
The algorithm is controlled by the following parameters:
•
AS_MEAS_TIME: this parameter controls the time interval for RSSI measurement
(ANT_SELECT_CONF register, allowed values 0...7). The actual measurement time is:
Equation 12
CHFLT_E
AS_meas_time
⋅2
⋅2
T meas = 24
---------------------------------------------------------------------------f XO
•
9.12
AS_ENABLE: this parameter enables the antenna switching function
(ANT_SELECT_CONF register: 0: disabled; 1: enabled).
Frequency hopping
In order to ensure good link reliability in an interference corrupted scenario, the device
supports frequency hopping, managed by the MCU; in particular, the SPIRIT1 supports slow
frequency hopping, meaning that the systems change frequency at a rate slower than the
information rate.
Depending on the desired blanking interval (the time during a hop), frequency hopping can
be done by performing the complete PLL calibration for each channel hop, or reading in the
suitable register calibration data calculated at startup and stored in the non-volatile memory
of the MCU. The former solution gives a long blanking interval but is more robust compared
with supply voltage and temperature variation. The latter provides a shorter blanking time
but is sensitive to voltage and temperature variation and requires memory space to store
calibration data for each channel involved in hopping.
c.
74/104
The user should make sure to provide a preamble sufficiently long to allow the algorithm to choose the final
antenna.
DocID022758 Rev 8
SPIRIT1
10
MCU interface
MCU interface
Communication with the MCU goes through a standard 4-wire SPI interface and 4 GPIOs.
The device is able to provide a system clock signal to the MCU.
MCU performs the following operations:
10.1
•
Program the SPIRIT1 in different operating modes by sending commands
•
Read and write buffered data, and status information from the SPI
•
Get interrupt requests from the GPIO pins
•
Apply external signals to the GPIO pins.
Serial peripheral interface
The SPIRIT1 is configured by a 4-wire SPI-compatible interface (CSn, SCLK, MOSI, and
MISO). More specifically:
•
CSn: chip select, active low
•
SCLK: bit clock
•
MOSI: data from MCU to SPIRIT1 (SPIRIT1 is the slave)
•
MISO: data from SPIRIT1 to MCU (MCU is the master).
As the MCU is the master, it always drives the CSn and SCLK. According to the active
SCLK polarity and phase, the SPIRIT1 SPI can be classified as mode 1 (CPOL=0,
CPHA=0), which means that the base value of SCLK is zero, data are read on the clock's
rising edge and data are changed on the clock's falling edge. The MISO is in tri-state mode
when CSn is high. All transfers are done most significant bit first.
The SPI can be used to perform the following operations:
•
Write data (to registers or FIFO queue)
•
Read data (from registers or FIFO queue)
•
Write commands.
The SPI communication is supported in all the active states, and also during the low power
state: STANDBY and SLEEP (see Table 20: States).
When accessing the SPI interface, the two status bytes of the MC_STATE[1:0] registers are
sent to the MISO pin. The timing diagrams of the three operations above are reported
below.
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104
MCU interface
SPIRIT1
Figure 14. SPI “write” operation
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Concerning the first byte, the MSB is an A/C bit (Address/Commands: 0 indicates that the
following byte is an address, 1 indicates that the following byte is a command code), while
the LSB is a W/R bit (Write/Read: 1 indicates a read operation). All other bits must be zero.
76/104
DocID022758 Rev 8
SPIRIT1
MCU interface
Read and write operations are persistently executed while CSn is kept active (low), the
address being automatically incremented (burst mode).
Accessing the FIFO is done as usual with the read and write commands, by putting, as the
address, the code 0xFF. Burst mode is available to access the sequence of bytes in the
FIFO. Clearly, RX-FIFO is accessed with a read operation, TX-FIFO with a write operation.
Details of the SPI parameters are reported below.
Table 35. SPI interface timing requirements
Symbol
fSCLK
tsp
10.2
Parameter
Min.
SCLK frequency
CSn low to positive edge on SCLK
2
Max.
Unit
10
MHz
µs
Interrupts
In order to notify the MCU of a certain number of events an interrupt signal is generated on
a selectable GPIO. The following events trigger an interrupt to the MCU:
Table 36. Interrupts
Bit
Events group
Interrupt event
0
RX data ready
1
RX data discarded (upon filtering)
2
TX data sent
3
Max. re-TX reached
4
CRC error
5
6
Packet oriented
TX FIFO underflow/overflow error
RX FIFO underflow/overflow error
7
TX FIFO almost full
8
TX FIFO almost empty
9
RX FIFO almost full
10
RX FIFO almost empty
11
Max. number of backoff during CCA
12
Valid preamble detected
13
14
Signal quality related
Sync word detected
RSSI above threshold (carrier sense)
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104
MCU interface
SPIRIT1
Table 36. Interrupts (continued)
Bit
Events group
Interrupt event
15
Wake-up timeout in LDCR mode(1)
16
READY(2)
17
STANDBY state switching in progress
18
Device status related
Low battery level
19
Power-on reset
20
Brownout event
21
LOCK
29
Timer related
30
Others
RX operation timeout
AES end–of–operation
1. The interrupt flag n.15 is set (and consequently the interrupt request) only when the XO clock is
available for the state machine. This time may be delayed compared to the actual timer
expiration. However, the real time event can be sensed putting the end-of-counting signal on a
GPIO output.
2. The interrupt flag n.16 is set each time the SPIRIT1 goes to READY state and the XO has
completed its setting transient (XO ready condition detected).
All interrupts are reported on a set of interrupt status registers and are individually
maskable. The interrupt status register must be cleared upon a read event from the MCU.
The status of all the interrupts is reported on the IRQ_STATUS[3:0] registers: bits are high
for the events that have generated any interrupts. The interrupts are individually maskable
using the IRQ_MASK[3:0] registers: if the mask bit related to a particular event is
programmed at 0, that event does not generate any interrupt request.
10.3
GPIOs
The total number of GPIO pins is 4. Each pin is individually configurable.
Digital outputs can be selected from the following (see GPIOx_CONF register):
Table 37. Digital outputs
I/O selection
78/104
Output signal
0
nIRQ (interrupt request, active low)
1
POR inverted (active low)
2
Wake-up timer expiration: ‘1’ when WUT has expired
3
Low battery detection: ‘1’ when battery is below threshold setting
4
TX data internal clock output (TX data are sampled on the rising edge of it)
5
TX state indication: ‘1’ when the SPIRIT1 is transiting in the TX state
6
TX FIFO almost empty flag
7
TX FIFO almost full flag
8
RX data output
DocID022758 Rev 8
SPIRIT1
MCU interface
Table 37. Digital outputs (continued)
I/O selection
Output signal
9
RX clock output (recovered from received data)
10
RX state indication: ‘1’ when SPIRIT1 is transiting in the RX state
11
RX FIFO almost full flag
12
RX FIFO almost empty flag
13
Antenna switch used for antenna diversity
14
Valid preamble detected flag
15
Sync word detected flag
16
RSSI above threshold (same indication as bit CS in the LINK_QUALIF[1] register)
17
MCU clock
18
TX or RX mode indicator (to enable an external range extender)
19
VDD (to emulate an additional GPIO of the MCU, programmable by SPI)
20
GND (to emulate an additional GPIO of the MCU, programmable by SPI)
21
External SMPS enable signal (active high)
22
Device in SLEEP or STANDBY states
23
Device not in SLEEP and not in STANDBY states
24
Device in LOCK state
25
Device waiting for a high level of the lock-detector output signal
26
Device waiting for timer expiration before starting to sample the lock-detector output
signal
27
Device waiting for a high level of the READY2 signal from XO
28
Device waiting for timer expiration to allow PM block settling
29
Device waiting for end of VCO calibration
30
Device enables the full circuitry of the SYNTH block
31
Device waiting for a high level of the RCCAL_OK signal from the RCO calibrator
All interrupts are reported on a set of interrupt status registers and are individually
maskable. The interrupt status register must be cleared upon a read event from the MCU.
The status of all the interrupts is reported on the IRQ_STATUS[3:0] registers: bits are high
for the events that have generated any interrupts. The interrupts are individually maskable
using the IRQ_MASK[3:0] registers: if the mask bit related to a particular event is
programmed at 0, that event does not generate any interrupt request.
Digital inputs can be selected from the following (see GPIOx_CONF register):
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104
MCU interface
SPIRIT1
Table 38. Digital inputs
I/O selection
Input signal
0
1 >> TX command
1
1 >> RX command
2
TX data input for direct modulation
3
Wake-up from external input (sensor output)
4
External clock @ 34.7 kHz (used for LDC modes timing)
From 5 to 31
Not used
The only available analog output is the temperature sensor, see Section 8.12.
10.4
MCU clock
SPIRIT1 can directly provide the system clock to the MCU in order to avoid the use of an
additional crystal. The clock signals for the MCU can be available on the GPIO pins. The
source oscillator can be the internal RCO or the XO depending on the active state. When
XO is active, it is the source clock (the RCO is not available in this condition).
In addition, different ratios are available and programmable through the MCU_CK_CONF
configuration register, as described in Table 39.
Table 39. MCU_CK_CONF configuration register
MCU_CK_CONF[4:0]
XO_RATIO
RCO_RATIO
Don’t care
0
Clock source
Division ratio
RCO
1
1
0
80/104
Don’t care
1/128
XO
1
1
2/3
2
1/2
3
1/3
4
1/4
5
1/6
6
1/8
7
1/12
8
1/16
9
1/24
10
1/36
11
1/48
12
1/64
DocID022758 Rev 8
SPIRIT1
MCU interface
Table 39. MCU_CK_CONF configuration register (continued)
MCU_CK_CONF[4:0]
Clock source
XO_RATIO
Division ratio
RCO_RATIO
13
1/96
14
1/128
15
1/192
In STANDBY state, no oscillator is available as the clock source. In order to allow the MCU
to better handle this event, and avoid a potential dead state situation, a dedicated procedure
is forecasted when the SPIRIT1 enters STANDBY state. A few extra clock cycles can be
provided to the MCU before actually stopping the clock (an interrupt is generated to notify
the MCU of this event).
The number of extra cycles can be programmed through the MCU_CK_CONF configuration
register to 0, 64, 256, or 512. The MCU can make use of these cycles to prepare to standby
or to switch on any auxiliary clock generator. The maximum transition time from READY to
STANDBY is then:
Equation 13
1
512
ΔT READY STANDBY = -------- ⋅ ----------------- = 98304
---------------f clk 1 ⁄ 192
f clk
where fclk is the digital clock frequency (typically 26 MHz).
The transition to SLEEP state causes the MCU clock source to change from XO to RCO.
Similarly, when the SPIRIT1 exits SLEEP to any active state, the source is the XO. Both
these transitions are implemented in order to be glitch-free. This is guaranteed by
synchronizing both transitions, switching on the rising or falling edge of the RCO clock.
The clock provided to the MCU depends on the current state:
Table 40. MCU clock vs. state
State
Source oscillator
MCU clock
SHUTDOWN
N/A
N/A
STANDBY
N/A
Tail
SLEEP
RC Osc
RC/1 or RC/128
READY
TUNING
RX
TX
XTAL
XTAL/N
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104
Register table
11
SPIRIT1
Register table
This section describes all the registers used to configure the SPIRIT1. The description is
structured in sections according to the register usage.
SPIRIT1 has three types of registers:
•
Read and write (R/W), which can be completely managed by SPI using READ and
WRITE operations
•
Read-only (R)
•
Read-and-reset (RR), is automatically cleared after a READ operation.
A further category of special registers collects the ones which cannot be categorized in any
of the three mentioned above R/W, R, or RR.
The fields named as “Reserved” must not be overridden by the user, otherwise, behavior is
not guaranteed.
The memory map is shown in the following table:
Table 41. General configuration registers
Register
ANA_FUNC_CONF[1]
Address
Bit
Field name
Reset
7:5
Reserved
000
4:2
GM_CONF[2:0]
011
0x00
1:0
82/104
SET_BLD_LVL[1:0]
DocID022758 Rev 8
00
R/W
Description
Sets the driver gm of the XO at
startup
R/W Sets the BLD threshold
00: 2.7 V
01: 2.5 V
10: 2.3 V
11: 2.1 V
SPIRIT1
Register table
Table 41. General configuration registers (continued)
Register
ANA_FUNC_CONF[0]
GPIO3_CONF
GPIO2_CONF
Address
0x01
Bit
Field name
Reset
7
Reserved
1
R/W
Description
6
24_26MHz_SELECT
1
1: 26 MHz configuration
0: 24 MHz configuration
(impact only RCO calibration
reference and loop filter
tuning)
5
AES_ON
0
1: AES engine enabled
0: reference signal from XO
circuit
R/W
1: reference signal from XIN
pin
4
EXT_REF
0
3
Reserved
0
2
BROWN_OUT
0
1: enables accurate brownout
detection
1
BATTERY_LEVEL
0
1: enables battery level
detector circuit
0
TS
0
1: enables the “temperature
sensor” function
7:3
GPIO_SELECT[4:0]
10100
2
Reserved
0
0x02
1:0
GPIO_MODE[1:0]
10
7:3
GPIO_SELECT[4:0]
10100
2
Reserved
0
0x03
1:0
GPIO_MODE
DocID022758 Rev 8
10
GPIO3 configuration (default:
digital GND)
GPIO3 mode:
R/W 01b: digital input
10b: digital output low power
11b: digital output high power
(default: digital output low
power)
GPIO2 configuration (default:
digital GND)
GPIO2 mode:
R/W 01b: digital input
10b: digital output low power
11b: digital output high power
(default: digital output low
power)
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Register table
SPIRIT1
Table 41. General configuration registers (continued)
Register
GPIO1_CONF
GPIO0_CONF
Address
Bit
Field name
Reset
7:3
GPIO_SELECT[4:0]
10100
2
Reserved
0
0x04
1:0
GPIO_MODE
10
7:3
GPIO_SELECT[4:0]
00001
2
Reserved
0
7
MCU_CK_CONF
XO_RCO_TEST
84/104
GPIO_MODE
EN_MCU_CLK
GPIO1 configuration (default:
digital GND)
GPIO1 mode:
R/W 01b: digital input
10b: digital output low power
11b: digital output high power
(default: digital output low
power)
GPIO0 configuration (default:
power-on reset signal)
10
0
1: The internal divider logic is
running, so the MCU clock is
available (but proper GPIO
configuration is needed)
Number of extra clock cycles
provided to the MCU before
switching to STANDBY state:
00: 0 extra clock cycle
R/W 01: 64 extra clock cycles
10: 256 extra clock cycles
11: 512 extra clock cycles
6:5
CLOCK_TAIL[1:0]
0
4:1
XO_RATIO[3:0]
0
Divider for the XO clock output
Divider for the RCO clock
output
0: 1
1: 1/128
0x06
0xB4
Description
GPIO0 mode:
R/W 00b: analog
01b: digital input
10b: digital output low power
11b: digital output high power
(default: digital output low
power)
0x05
1:0
R/W
0
RCO_RATIO
0
7:4
Reserved
0010
3
PD_CLKDIV
0
2:0
Reserved
001
DocID022758 Rev 8
1: disable both dividers of the
digital clock (and reference
clock for the SMPS) and IFADC clock.
SPIRIT1
Register table
Table 41. General configuration registers (continued)
Register
SYNTH_CONFIG[0]
SYNTH_CONFIG[1]
IF_OFFSET_ANA
Address
0x9F
0x9E
0x07
Bit
Field name
Reset
7
SEL_TSPLIT
0
6:0
Reserved
0100000
R/W
Description
0: split time: 1.75 ns
R/W 1: split time: 3.47 ns
Enable division by 2 on the
reference clock:
0: fREF = fXO frequency
1: fREF = fXO frequency / 2
7
REFDIV
0
6:3
Reserved
1011
2
VCO_L_SEL
0
1: enable VCO_L
1
VCO_H_SEL
1
1: enable VCO_H
0
Reserved
1
7:0
IF_OFFSET_ANA
0xA3
R/W
Intermediate frequency setting
R/W for the analog RF synthesizer.
(see Section 9.4)
Table 42. Radio configuration registers (analog blocks)
Register name
SYNT3
Address
Bit
Field Name
Reset
7:5
WCP[2:0]
000
R/W
Description
Set the charge pump current
according to the VCO
frequency. See Table 26.
4:0
SYNT[25:21]
01100
R/W SYNT[25:21], highest 5 bits of
the PLL programmable divider
The valid range depends on
fXO and REFDIV settings; for
fXO=26MHz. See Equation 3
0x08
SYNT2
0x09
7:0
SYNT[20:13]
0x84
SYNT[20:13], intermediate bits
R/W of the PLL programmable
divider. See Equation 3
SYNT1
0x0A
7:0
SYNT[12:5]
0xEC
SYNT[12:5], intermediate bits
R/W of the PLL programmable
divider. See Equation 3
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104
Register table
SPIRIT1
Table 42. Radio configuration registers (analog blocks) (continued)
Register name
SYNT0
Address
Bit
Field Name
Reset
R/W
Description
7:3
SYNT[4:0]
01010
SYNT[4:0], lowest bits of the
R/W PLL programmable divider.
See Equation 3
2:0
BS
001
Synthesizer band select. This
parameter selects the out-ofloop divide factor of the
synthesizer (B in Equation 3 ).
1: 6 Band select factor for high
R/W band
3: 12 Band select factor for
middle band
4: 16 Band select factor for low
band
5: 32 Band select factor for
very low band
0x0B
CHSPACE
0x0C
7:0
CH_SPACING
0xFC
Channel spacing in steps of
R/W fXO/215 (~793 for fXO = 26 MHz,
~732 for fXO = 24 MHz).
IF_OFFSET_DIG
0x0D
7:0
IF_OFFSET_DIG
0xA3
Intermediate frequency setting
R/W for the digital shift-to-baseband
(see Section 9.4)
FC_OFFSET[1]
0x0E
7:4
Reserved
0
3:0
FC_OFFSET[11:8]
0
FC_OFFSET[0]
0x0F
7:0
FC_OFFSET[7:0]
0
7
Reserved
0
PA_POWER[8]
0x10
6:0
PA_LEVEL_7
7
Reserved
6:0
PA_LEVEL_6
7
Reserved
6:0
PA_LEVEL_5
7
Reserved
6:0
PA_LEVEL_4
7
Reserved
6:0
PA_LEVEL_3
PA_POWER[7]
0x11
PA_POWER[6]
0x12
PA_POWER[5]
0x13
PA_POWER[4]
0x14
86/104
Carrier offset in steps of fXO/218
R/W and represented as 12 bits 2complement integer. It is added
/ subtracted to the carrier
frequency set by the SYNTx
register. This register can be
R/W
used to set a fixed correction
value obtained e.g. from crystal
measurements.
Output power level for 8th slot
000001 R/W (+12 dBm)
1
0
Output power level for 7th slot
000111 R/W (+6 dBm)
0
0
Output power level for 6th slot
001101 R/W (0 dBm)
0
0
Output power level for 5th slot (010010 R/W 6 dBm)
1
0
Output power level for 4th slot (011010 R/W 12 dBm)
1
DocID022758 Rev 8
SPIRIT1
Register table
Table 42. Radio configuration registers (analog blocks) (continued)
Register name
Address
PA_POWER[3]
0x15
PA_POWER[2]
0x16
PA_POWER[1]
0x17
PA_POWER[0]
0x18
Bit
Field Name
Reset
7
Reserved
0
6:0
PA_LEVEL_2
7
Reserved
6:0
PA_LEVEL_1
7
Reserved
6:0
PA_LEVEL_0
R/W
Description
Output power level for 3rd slot
100000 R/W (-18 dBm)
0
0
Output power level for 2nd slot
100111 R/W (-24 dBm)
0
0
Output power level for first slot
000000 R/W (-30 dBm)
0
Output stage additional load
capacitors bank (to be used to
optimize the PA for different
sub-bands):
00: 0 pF
01: 1.2 pF
10: 2.4 pF
R/W
11: 3.6 pF
7:6
CWC[1:0]
00
5
PA_RAMP_ENABLE
0
1: enable the power ramping
4:3
PA_RAMP_STEP_W
IDTH[1:0]
00
Step width (unit: 1/8 of bit
period)
2:0
PA_LEVEL_MAX_IN
DEX
111
Final level for power ramping or
selected output power index.
Table 43. Radio configuration registers (digital blocks)
Register name
Address
Bit
Field Name
Reset
R/W
Description
MOD1
0x1A
7:0
DATARATE_M
0x83
R/W
The mantissa value of the data
rate equation (see Equation 11)
7
CW
0
1: enable the CW transmit
mode
6
BT_SEL
0
Select BT value for GFSK
0: BT = 1
1: BT = 0.5
MOD0
0x1B
5:4
MOD_TYPE[1:0]
01
3:0
DATARATE_E
1010
DocID022758 Rev 8
R/W Modulation type
0: 2-FSK
1: GFSK
2: ASK/OOK
3: MSK
The exponent value of the data
rate equation (see Equation 11)
87/104
104
Register table
SPIRIT1
Table 43. Radio configuration registers (digital blocks) (continued)
Register name
FDEV0
CHFLT
AFC2
AFC1
AFC0
RSSI_FLT
RSSI_TH
88/104
Address
0x1C
Bit
Field Name
Reset
7:4
FDEV_E[3:0]
0100
3
CLOCK_REC_ALGO
_SEL
0
2:0
FDEV_M
101
The mantissa value of the
frequency deviation equation
(see Equation 10)
7:4
CHFLT_M[3:0]
0010
The mantissa value of the
channel filter according to
Table 32
0x1D
R/W
The exponent value of the
frequency deviation equation
(see Equation 10)
R/W
R/W
0x22
The exponent value of the
channel filter according to
Table 32
CHFLT_E
0011
7
AFC_FREEZE_ON_
SYNC
0
6
AFC_ENABLE
1
1: enable AFC(see Section 8.8:
AFC)
Select AFC mode:
0: AFC loop closed on slicer
1: AFC loop closed on second
conversion stage
1: enable the freeze AFC
R/W correction upon sync word
detection
5
AFC_MODE
0
4:0
AFC_PD_LEAKAGE
01000
Peak detector leakage
7:0
AFC_FAST_PERIOD
0x18
R/W Length of the AFC fast period
7:4
AFC_FAST_GAIN_L
OG2[3:0]
0010
3:0
AFC_SLOW_GAIN_L
OG2
0101
7:4
RSSI_FLT[3:0]
1110
3:2
CS_MODE
00
Carrier sense mode (see
Section 9.10.2)
1:0
OOK_PEAK_DECAY
11
Peak decay control for OOK: 3
slow decay; 0 fast decay
0x20
0x21
Select PLL or DLL mode for
symbol timing recovery
3:0
0x1E
0x1F
Description
7:0
RSSI_THRESHOLD
DocID022758 Rev 8
R/W
0x24
AFC loop gain in fast mode
(log2)
AFC loop gain in slow mode
(log2)
R/W Gain of the RSSI filter
Signal detect threshold in 0.5
dB steps,
R/W
-120 dBm corresponds to 0x14.
(see Section 9.10.1)
SPIRIT1
Register table
Table 43. Radio configuration registers (digital blocks) (continued)
Register name
CLOCKREC
AGCCTRL2
AGCCTRL1
AGCCTRL0
ANT_SELECT_CONF
Address
0x23
0x24
0x25
0x26
0x27
Bit
Field Name
Reset
7:5
CLK_REC_P_GAIN[
2:0]
2
4
PSTFLT_LEN
1
3:0
CLK_REC_I_GAIN
8
7:4
Reserved
0010
3:0
MEAS_TIME
0010
7:4
THRESHOLD_HIGH[
3:0]
0110
3:0
THRESHOLD_LOW
0101
7
AGC ENABLE
1
R/W
Description
Clock recovery loop gain (log2)
Post-filter:
0: 8 symbols,
R/W
1: 16 symbols
Integral gain for the clock
recovery loop (used in PLL
mode)
R/W
R/W
Measure time
High threshold for the AGC
Low threshold for the AGC
1: enable AGC.
000101 R/W
0
6:0
Reserved
7:5
Reserved
000
4
CS_BLANKING
0
3
AS_ENABLE
0
2:0
AS_MEAS_TIME
101
1: do not fill the RX FIFO with
the data received if the signal is
R/W below the CS threshold
1: enable antenna switching
Measurement time
Table 44. Packet/protocol configuration registers
Register name
PCKTCTRL4
Address
0x30
Bit
Field Name
Reset
7:5
Reserved
000
4:3
ADDRESS_LEN[1:0]
00
2:0
CONTROL_LEN
000
DocID022758 Rev 8
R/W
Description
Length of address field in
bytes:
R/W 0 or 1: Basic
2: STack
Length of control field in
bytes
89/104
104
Register table
SPIRIT1
Table 44. Packet/protocol configuration registers (continued)
Register name
Address
Bit
7:6
PCKTCTRL3
PCKTCTRL2
PCKTLEN1
90/104
PCKT_FRMT[1:0]
Reset
Description
00
R/W RX mode:
0: normal mode,
1: direct through FIFO,
2: direct through GPIO
5:4
RX_MODE[1:0]
00
3:0
LEN_WID
0111
7:3
PREAMBLE_LENGTH[4
:0]
00011
Length of preamble field in
bytes (from 1 to 32)
2:1
SYNC_LENGTH[1:0]
11
Length of sync field in bytes
(from 1 to 4)
0
R/W Packet length mode.
0: fixed,
1: variable (in variable mode
the field LEN_WID of
PCKTCTRL3 register must
be configured)
0x32
FIX_VAR_LEN
7:5
CRC_MODE[2:0]
001
4
WHIT_EN[0]
0
0x33
0x34
R/W
Format of packet.
0: basic,
2: WM-Bus,
3: STack
(see Section 9.7)
0x31
0
PCKTCTRL1
Field Name
3:2
TXSOURCE[1:0]
00
1
Reserved
0
0
FEC_EN
0
7:0
PCKTLEN1
0
DocID022758 Rev 8
Size in number of binary digit
of length field
CRC:
0: No CRC,
1: 0x07,
2: 0x8005,
3: 0x1021,
4: 0x864CBF
1: enable the whitening mode
on the data
(see Section 9.6.3)
R/W TX source data:
0: normal mode,
1: direct through FIFO,
2: direct through GPIO,
3: PN9
1: enable the FEC encoding
in TX or enable the Viterbi
decoding in RX
(see Section 9.6.1)
R/W
Length of packet in bytes
(MSB)
SPIRIT1
Register table
Table 44. Packet/protocol configuration registers (continued)
Register name
Address
Bit
Field Name
Reset
R/W
PCKTLEN0
0x35
7:0
PCKTLEN0
0x14
R/W
SYNC4
0x36
7:0
SYNC4
0x88
R/W Sync word 4
SYNC3
0x37
7:0
SYNC3
0x88
R/W Sync word 3
SYNC2
0x38
7:0
SYNC2
0x88
R/W Sync word 2
SYNC1
0x39
7:0
SYNC1
0x88
R/W Sync word 1
7:6
SQI_TH[1:0]
00
5:2
PQI_TH[3:0]
0000
1
SQI_EN[0]
1
1: enable SQI
0
PQI_EN[0]
0
1: enable PQI
QI
0x3A
Description
Length of packet in bytes
(LSB)
SQI threshold (see
Section 9.10.5)
PQI threshold (see
R/W Section 9.10.4)
MBUS_PRMBL
0x3B
7:0
MBUS_PRMBL[7:0]
0x20
R/W
MBUS preamble length in
chip sequence ‘01’
MBUS_PSTMBL
0x3C
7:0
MBUS_PSTMBL[7:0]
0x20
R/W
MBUS postamble length in
chip sequence ‘01’
7:4
Reserved
00000
MBUS_CTRL
0x3D
FIFO_CONFIG[3]
0x3E
FIFO_CONFIG[2]
0x3F
FIFO_CONFIG[1]
0x40
FIFO_CONFIG[0]
0x41
PCKT_FLT_GOALS[1
2]
0x42
3:1
MBUS_SUBMODE[2:0]
000
0
Reserved
0
7
Reserved
0
6:0
RXAFTHR [6:0]
7
Reserved
6:0
RXAETHR [6:0]
7
Reserved
6:0
TXAFTHR [6:0]
7
Reserved
6:0
TXAETHR [6:0]
7:0
CONTROL0_MASK
DocID022758 Rev 8
MBUS sub mode: allowed
values are 0, 1, 3 and 5
WM-BUS sub mode:
R/W 0: S1 S2 long header,
1: S1m S2 T2 other to meter,
3: T1 T2 meter to other,
5: R2 short header
R/W
110000 R/W
0
R/W
110000 R/W
0
FIFO almost full threshold for
TX FIFO
R/W
110000 R/W
0
FIFO almost empty threshold
for RX FIFO
R/W
110000 R/W
0
FIFO almost full threshold for
RX FIFO
R/W
FIFO almost empty threshold
for TX FIFO
For received packet only: all
0s: no filtering on control field
91/104
104
Register table
SPIRIT1
Table 44. Packet/protocol configuration registers (continued)
Register name
Address
Bit
Field Name
Reset
R/W
Description
PCKT_FLT_GOALS[1
1]
0x43
7:0
CONTROL1_MASK
0
R/W
For received packet only: all
0s: no filtering on control field
PCKT_FLT_GOALS[1
0]
0x44
7:0
CONTROL2_MASK
0
R/W
For received packet only: all
0s: no filtering on control field
PCKT_FLT_GOALS[9]
0x45
7:0
CONTROL3_MASK
0
R/W
For received packet only: all
0s: no filtering on control field
PCKT_FLT_GOALS[8]
0x46
7:0
CONTROL0_FIELD
0
Control field (byte 3) to be
R/W used as reference for
receiver
PCKT_FLT_GOALS[7]
0x47
7:0
CONTROL1_FIELD
0
Control field (byte 2) to be
R/W used as reference for
receiver
PCKT_FLT_GOALS[6]
0x48
7:0
CONTROL2_FIELD
0
Control field (byte 1) to be
R/W used as reference for
receiver
PCKT_FLT_GOALS[5]
0x49
7:0
CONTROL3_FIELD
0
Control field (byte 0) to be
R/W used as reference for
receiver
PCKT_FLT_GOALS[4]
0x4A
7:0
RX_SOURCE_MASK
0
R/W
For received packet only: all
0s: no filtering
PCKT_FLT_GOALS[3]
0x4B
7:0
RX_SOURCE_ADDR
0
R/W
RX packet source / TX packet
destination fields
PCKT_FLT_GOALS[2]
0x4C
7:0
BROADCAST
0
R/W Broadcast address
PCKT_FLT_GOALS[1]
0x4D
7:0
MULTICAST
0
R/W Multicast address
PCKT_FLT_GOALS[0]
0x4E
7:0
TX_SOURCE_ADDR
0
R/W
92/104
DocID022758 Rev 8
TX packet source / RX packet
destination fields
SPIRIT1
Register table
Table 44. Packet/protocol configuration registers (continued)
Register name
Address
Bit
Field Name
Reset
7
Reserved
0
6
5
PCKT_FLT_OPTIONS
PROTOCOL[2]
RX_TIMEOUT_AND_O
R_SELECT
CONTROL_FILTERING
Description
1
1: ‘OR’ logical function
applied to CS/SQI/PQI values
(masked by 7:5 bits in
PROTOCOL register:
CS_TIMEOUT_MASK,
SQI_TIMEOUT_MASK,
PQI_TIMEOUT_MASK)
1
1: RX packet accepted if its
control fields match with
masked CONTROLx_FIELD
registers
1
1: RX packet accepted if its
source field matches with
masked
R/W RX_SOURCE_ADDR
register
4
SOURCE_FILTERING
3
DEST_VS_SOURCE
_ADDR
0
1: RX packet accepted if its
destination address matches
with TX_SOURCE_ADDR
reg.
2
DEST_VS_MULTICAST
_ADDR
0
1: RX packet accepted if its
destination address matches
with MULTICAST register
1
DEST_VS_
BROADCAST_ADDR
0
1: RX packet accepted if its
destination address matches
with BROADCAST
reg.
0
CRC_CHECK
0
1: packet discarded if CRC
not valid.
23
CS_TIMEOUT_MASK
0
1: CS value contributes to
timeout disabling
22
SQI_TIMEOUT_MASK
0
1: SQI value contributes to
timeout disabling
21
PQI_TIMEOUT_MASK
0
1: PQI value contributes to
timeout disabling
0x4F
0x50
R/W
20:1 TX_SEQ_NUM_RELOA
9
D[1:0]
0
TX sequence number to be
R/W used when counting reset is
required using the related
command.
18
RCO_CALIBRATION
0
1: enable the automatic RCO
calibration
17
VCO_CALIBRATION
1
1: enable the automatic VCO
calibration
16
LDC_MODE
0
1: LDC mode on
DocID022758 Rev 8
93/104
104
Register table
SPIRIT1
Table 44. Packet/protocol configuration registers (continued)
Register name
PROTOCOL[1]
PROTOCOL[0]
TIMERS[5]
TIMERS[4]
94/104
Address
0x51
0x52
0x53
0x54
Bit
Field Name
Reset
R/W
Description
15
LDC_RELOAD_ON_SY
NC
0
1: LDC timer is reloaded with
the value stored in the
LDC_RELOAD registers
14
PIGGYBACKING
0
1: PIGGYBACKING enabled
13:1
2
Reserved
00
1: reload the back-off random
generator seed using the
R/W value written in the
BU_COUNTER_SEED_MSB
YTE / LSBYTE registers
11
SEED_RELOAD
0
10
CSMA_ON
0
1: CSMA channel access
mode enabled
9
CSMA_PERS_ON
0
1: CSMA persistent (no backoff) enabled
8
AUTO_PCKT_FLT
0
1: automatic packet filtering
mode enabled
7:4
NMAX_RETX[3:0]
0
Max. number of re-TX (from 0
to 15).
0: re-transmission is not
performed
3
NACK_TX
1
1: field NO_ACK=1 on
transmitted packet
2
AUTO_ACK
0
1
PERS_RX
0
0
PERS_TX
0
47:4
0
39:3
2
RX_TIMEOUT_PRESC
ALER[7:0]
RX_TIMEOUT_COUNT
ER[7:0]
DocID022758 Rev 8
R/W 1: automatic
acknowledgement after
correct packet reception
1: persistent reception
enabled
1: persistent transmission
enabled
1
Prescaler value of the RX
TIMEOUT timer. When this
timer expires the SPIRIT1
R/W
exits RX state. Can be
controlled using the quality
indicator (SQI, LQI, PQI, CS).
0
Counter value of the RX
TIMEOUT timer. When this
timer expires the SPIRIT1
R/W
exits RX state. Can be
controlled using the quality
indicator (SQI, LQI, PQI, CS)
SPIRIT1
Register table
Table 44. Packet/protocol configuration registers (continued)
Register name
TIMERS[3]
TIMERS[2]
TIMERS[1]
TIMERS[0]
CSMA_CONFIG[3]
CSMA_CONFIG[2]
CSMA_CONFIG[1]
CSMA_CONFIG[0]
Address
Bit
0x55
31:2
4
0x56
23:1
6
0x57
0x58
0x64
0x65
15:8
7:0
7:0
Field Name
LDC_PRESCALER[7:0]
LDC_COUNTER[7:0]
LDC_RELOAD_PRESC
ALER[7:0]
LDC_RELOAD_COUNT
ER[7:0]
BU_COUNTER_SEED_
MSBYTE
Reset
1
0
Counter value of the LDC
wake-up timer. When this
R/W
timer expires the SPIRIT1
exits SLEEP state.
1
Prescaler value of the LDC
reload timer. When this timer
expires the SPIRIT1 exits
SLEEP state. The reload
R/W timer value is used if the
SYNC word is detected (by
the receiver) or if the
LDC_RELOAD command is
used.
0
Counter part of the LDC
reload value timer. When this
timer expires the SPIRIT1
exits SLEEP state. The
R/W reload timer value is used if
the SYNC word is detected
(by the receiver) or if the
LDC_RELOAD command is
used.
0xFF
The MSB value of the counter
of the seed of the random
R/W number generator used to
apply the BBE algorithm
during the CSMA algorithm
The LSB value of the counter
seed of the random number
R/W generator used to apply the
BBE algorithm during the
CSMA algorithm
7:0
BU_COUNTER_SEED_
LSBYTE
0
7:2
BU_PRESCALER[5:0]
00000
1
1:0
CCA_PERIOD
00
7:4
CCA_LENGTH[3:0]
0000
3
Reserved
0
2:0
NBACKOFF_MAX
000
DocID022758 Rev 8
Description
Prescaler value of the LDC
wake-up timer. When this
R/W
timer expires the SPIRIT1
exits SLEEP state.
0x66
0x67
R/W
The prescaler value used to
program the back-off unit BU
R/W Used to program the T
cca
time (64 / 128 / 256 / 512 ×
Tbit)
Used to program the Tlisten
time
R/W
Max. number of back-off
cycles
95/104
104
Register table
SPIRIT1
Table 44. Packet/protocol configuration registers (continued)
Register name
Address
Bit
Field Name
Reset
R/W
Description
TX_CTRL_FIELD[3]
0x68
7:0
TX_CTRL3
0
R/W
Control field value to be used
in TX packet as byte n.3
TX_CTRL_FIELD[2]
0x69
7:0
TX_CTRL2
0
R/W
Control field value to be used
in TX packet as byte n.2
TX_CTRL_FIELD[1]
0x6A
7:0
TX_CTRL1
0
R/W
Control field value to be used
in TX packet as byte n.1
TX_CTRL_FIELD[0]
0x6B
7:0
TX_CTRL0
0
R/W
Control field value to be used
in TX packet as byte n.0
7
Reserved
0
6
EN_TS_BUFFER
0
1: temperature sensor output
is buffered
5
DISABLE_SMPS
0
0: enable internal SMPS
1: disable internal SMPS
4
Reserved
0
3
SET_SMPS_VTUNE
1
Sets the SMPS Vtune voltage
2
SET_SMPS_PLLBW
1
Sets the SMPS bandwidth
1:0
Reserved
00
PM_CONFIG[2]
PM_CONFIG[1]
PM_CONFIG[0]
XO_RCO_CONFIG
0xA4
R/W
7
EN_RM
0
6:0
KRM[14:8]
01000
00
7:0
KRM[7:0]
0
7:4
Reserved
1110
3
EXT_RCOSC
0
2:0
Reserved
001
0xA5
0xA6
0xA7
TEST_SELECT
0xA8
7:0
Reserved
0x00
PM_TEST
0xB2
7:0
Reserved
0x42
96/104
DocID022758 Rev 8
0: divider by 4 enabled
(SMPS' switching frequency
is FSW=FOSC/4)
1: rate multiplier enabled
R/W (SMPS' switching frequency
is FSW=KRM*FOSC/(2^15)
R/W
R/W
R/W
Sets the divider ration of the
rate multiplier.
1: the 34.7kHz signal must be
supplied from a GPIO pin
SPIRIT1
Register table
Table 45. Frequently used registers
Register name
Address
CHNUM
0x6C
VCO_CONFIG
0xA1
RCO_VCO_CALIBR_IN
[2]
0x6D
Bit
Field Name
Reset
7:0
CH_NUM
0
7:6
Reserved
00
5:0
VCO_GEN_CURR
010001
7:4
RWT_IN[3:0]
0111
3:0
RFB_IN[4:1]
0000
7
RFB_IN[0]
0
R/W
Description
Channel number. This value is
multiplied by the channel
spacing and added to the
R/W
synthesizer base frequency to
generate the actual RF carrier
frequency. See Equation 3
R/W
R/W
Set the VCO current
RWT word value for the RCO
RFB word value for the RCO
RCO_VCO_CALIBR_IN
[1]
0x6E
RCO_VCO_CALIBR_IN
[0]
0x6F
AES_KEY_IN[15]
0x70
7:0
AES_KEY15
0
R/W
AES engine key input (128
bits)
AES_KEY_IN[14]
0x71
7:0
AES_ KEY14
0
R/W
AES engine key input (128
bits)
…
7:0
…
…
…
AES_KEY_IN[1]
0x7E
7:0
AES_ KEY1
0
R/W
AES engine key input (128
bits)
AES_KEY_IN[0]
0x7F
7:0
AES_ KEY0
0
R/W
AES engine key input (128
bits)
AES_DATA_IN[15]
0x80
7:0
AES_IN15
0
R/W
AES engine data input (128
bits)
0x81
7:0
AES_IN14
0
R/W
AES engine data input (128
bits)
…
…
…
…
…
AES_DATA_IN[1]
0x8E
7:0
AES_IN1
0
R/W
AES engine data input (128
bits)
AES_DATA_IN[0]
0x8F
7:0
AES_IN0
0
R/W
AES engine data input (128
bits)
IRQ_MASK[3]
0x90
7:0
INT_MASKT[31:24]
0
The IRQ mask register to route
R/W the IRQ information to a GPIO.
See Table 36.
IRQ_MASK[2]
0x91
7:0
INT_MASK [23:16]
0
The IRQ mask register to route
R/W the IRQ information to a GPIO.
See Table 36.
AES_DATA_IN[14]
6:0
7
6:0
VCO_CALIBR_TX[6: 100100 R/W Word value for the VCO to be
0]
0
used in TX mode
Reserved
0
VCO_CALIBR_RX[6: 100100 R/W Word value for the VCO to be
0]
0
used in RX mode
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…
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Register table
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Table 45. Frequently used registers (continued)
Register name
Address
Bit
Field Name
Reset
IRQ_MASK[1]
0x92
7:0
INT_MASK[15:8]
0
The IRQ mask register to route
R/W the IRQ information to a GPIO.
See Table 36.
IRQ_MASK[0]
0x93
7:0
INT_MASK [7:0]
0
The IRQ mask register to route
R/W the IRQ information to a GPIO.
See Table 36.
7:2
Reserved
001101
Reserved do not modify
1
DEM_ORDER
1
0
Reserved
1
7
Reserved
0
6
EN_TS_BUFFER
0
5
DISABLE_SMPS
0
7:4
Reserved
0101
3
ANT_SELECT
0
2
TX_FIFO_FULL
0
1
RX_FIFO_EMPTY
0
1: RX FIFO is empty
0
ERROR_LOCK
0
1: RCO calibrator error
7:1
STATE[6:0]
0
Current MC state. See
Table 20.
0
XO_ON
0
7:6
Reserved
0
5:4
TX_SEQ_NUM
0
DEM_CONFIG
PM_CONFIG
MC_STATE[1]
MC_STATE[0]
TX_PCKT_INFO
RX_PCKT_INFO
0xA3
0xA4
0xC0
0xC1
0xC2
0xC3
R/W
R/W
N_RETX
0
7:3
Reserved
0
2
NACK_RX
0
1:0
RX_SEQ_NUM
0
Set it to 0 during radio
initialization
Reserved do not modify
1: temperature sensor output
R/W is buffered
0: enable internal SMPS
1: disable internal SMPS
Currently selected antenna
R
R
1: TX FIFO is full
1: XO is operating
Current TX packet sequence
number
R
3:0
Description
R
Number of transmission done
at the end of a TX sequence.
The value is updated at the
Max. number of retransmission
reached or at the reception of
an ACK packet.
NACK field of the received
packet
Sequence number of the
received packet
AFC_CORR
0xC4
7:0
AFC_CORR[7:0]
0
R
AFC word of the received
packet
LINK_QUALIF[2]
0xC5
7:0
PQI[7:0]
0
R
PQI value of the received
packet
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Register table
Table 45. Frequently used registers (continued)
Register name
LINK_QUALIF[1]
LINK_QUALIF[0]
Address
0xC6
Bit
Field Name
Reset
7
CS
0
6:0
SQI[6:0]
0
7:4
LQI [3:0]
0
0xC7
R/W
Carrier sense indication
R
R
3:0
AGC_WORD
0
Description
SQI value of the received
packet
LQI value of the received
packet
AGC word of the received
packet
RSSI level of the received
packet
RSSI_LEVEL
0xC8
7:0
RSSI_LEVEL
0
R
RX_PCKT_LEN[1]
0xC9
7:0
RX_PCKT_LEN1
0
R
RX_PCKT_LEN[0]
0xCA
7:0
RX_PCKT_LEN0
0
R
CRC_FIELD[2]
0xCB
7:0
CRC2
0
R
CRC field of the received
packet, byte 2
CRC_FIELD[1]
0xCC
7:0
CRC1
0
R
CRC field of the received
packet, byte 1
CRC_FIELD[0]
0xCD
7:0
CRC0
0
R
CRC field of the received
packet, byte 0
RX_CTRL_FIELD[3]
0xCE
7:0
RX_CTRL0
0
R
Control field(s) of the received
packet, byte 0
RX_CTRL_FIELD[2]
0xCF
7:0
RX_CTRL1
0
R
Control field(s) of the received
packet, byte 1
RX_CTRL_FIELD[1]
0xD0
7:0
RX_CTRL2
0
R
Control field(s) of the received
packet, byte 2
RX_CTRL_FIELD[0]
0xD1
7:0
RX_CTRL3
0
R
Control field(s) of the received
packet, byte 3
RX_ADDR_FIELD[1]
0xD2
7:0
ADDR1
0
R
Source address field of the RX
packet.
RX_ADDR_FIELD[0]
0xD3
7:0
ADDR0
0
R
Destination address field of the
RX packet.
AES_ DATA_OUT[15]
0xD4
7:0
AES_OUT15
0
R
AES engine data output (128
bits)
0xD5
7:0
AES_OUT14
0
R
AES engine data output (128
bits)
…
…
…
…
…
…
AES_ DATA_OUT[1]
0xE2
7:0
AES_OUT1
0
R
AES engine data output (128
bits)
AES_ DATA_OUT[0]
0xE3
7:0
AES_OUT0
0
R
AES engine data output (128
bits)
AES_ DATA_OUT[14]
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Length (number of bytes) of
the received packet:
RX_PCKT_LEN=RX_PCKT_L
EN1 × 256 + RX_PCKT_LEN0
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Register table
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Table 45. Frequently used registers (continued)
Register name
RCO_VCO_CALIBR_O
UT[1]
RCO_VCO_CALIBR_O
UT[0]
LINEAR_FIFO_STATUS
[1]
Address
Bit
Field Name
Reset
7:4
RWT_OUT[3:0]
0
0xE4
0xE5
0xE6
R/W
RWT word from internal RCO
calibrator
R
3:0
RFB_OUT[4:1]
0
7
RFB_OUT[0]
0
6:0
VCO_CALIBR_DATA
0
7
Reserved
0
6:0
ELEM_TXFIFO
0
7
Reserved
0
6:0
ELEM_RXFIFO
0
Description
RFB word from internal RCO
calibrator
R
Output word from internal VCO
calibrator
R
Number of elements in the
linear TX FIFO (from 0 to 96
bytes)
R
Number of elements in the
linear RX FIFO (from 0 to 96
bytes)
LINEAR_FIFO_STATUS
[0]
0xE7
IRQ_STATUS[3]
0xFA
7:0
INT_EVENT[31:24]
0
RR
The IRQ status register. See
Table 36.
IRQ_STATUS[2]
0xFB
7:0
INT_EVENT[23:16]
0
RR
The IRQ status register. See
Table 36.
IRQ_STATUS[1]
0xFC
7:0
INT_EVENT[15:8]
0
RR
The IRQ status register. See
Table 36.
IRQ_STATUS[0]
0xFD
7:0
INT_EVENT[7:0]
0
RR
The IRQ status register. See
Table 36.
Table 46. General information
Register
DEVICE_INFO[1:0]
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Address
Bit
Field name
Reset
R/W
0xF0
7:0
PARTNUM[7:0]
0x01
R
Device part number
0xF1
7:0
VERSION[7:0]
0x30
R
Device version number
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Description
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12
Package mechanical data
Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK
specifications, grade definitions, and product status are available at: www.st.com.
ECOPACK is an ST trademark.
Table 47. QFN20 (4 x 4 mm.) mechanical data
mm.
Dim.
Min.
Typ.
Max.
0.80
0.90
1.00
A1
0.02
0.05
A2
0.65
1.00
A3
0.25
A
b
0.18
0.23
0.30
D
3.85
4.00
4.15
D2
2.55
2.60
2.65
E
3.85
4.00
4.15
E2
2.55
2.60
2.65
e
0.45
0.50
0.55
L
0.35
0.55
0.75
ddd
0.08
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Package mechanical data
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Figure 17. QFN20 (4 x 4 mm.) drawing dimension
7169619_G
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13
Revision history
Revision history
Table 48. Document revision history
Date
Revision
06-Feb-2012
1
Initial release.
26-Apr-2012
2
Update RF performance figures in the whole document.
Changed pinout for pin 11.
Minor text changes.
3
Updated tables 4, 8, 11, 13, 20, 13, 23, 34, 40, 41, 44 and 45.
Updated Section 9.4: Intermediate frequency setting and Section 12:
Package mechanical data.
Minor text changes to improve readability.
Document status changed from preliminary to production data.
13-Feb-2013
4
Updated tables 7, 8, 12, 13, 13, 19, 41, 42, and 45.
Updated Section 3.1, Section 6.2.1, Section 7.4 and Section 9.7.5
Inserted Table 9: Power consumption static modes, Figure 3:
Application diagram for Tx boost mode, Figure 4: Application
diagram for SMPS OFF mode, Section 7.3: Low duty cycle reload
mode Section 9.10.1: RSSI and Table 3.
Added Section 8.1.1: Switching frequency.
Minor text changes to improve readability.
06-May-2013
5
Updated tables 3 and 4.
Inserted new Section 8.7 and Section 8.9.
Minor text changes.
11-Feb-2015
6
Updated Features in cover page, Section 7.2: Timer usage,
Section 7.3: Low duty cycle reload mode, Table 7: Recommended
operating conditions, Table 13: RF receiver characteristics sensitivity, added Table footnote “3” to Table 20: States, Section 9.1
and Section 9.8.
27-May-2015
7
Updated: Chapter 6.2.5: Crystal oscillator, Chapter 8.5: Oscillator
and RF synthesizer, and Table 37: Digital outputs.
25-Jun-2015
8
Minor text change to improve readability.
05-Oct-2012
Changes
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Purchasers are solely responsible for the choice, selection, and use of ST products and ST assumes no liability for application assistance or
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