User's Manual

User Manual
2017Cervis, Inc.
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4.2 Operating Current
The SRF310 RTM has four primary operating conditions that draw differing amounts of current
from to 3.0-3.3V power source:
Off RFIC is powered down, minimal load
PLL_ON RFIC is ready to transmit or receive, ~5mA
RX RFIC is receiving a message, ~25mA
TX RFIC is transmitting, ~25-100mA, depending on TX output power
In TX mode the operating current may be less than the maximum if the drive to the external
PA is reduced because the full RF output power is not required.
4.3 SPI Interface
The SPI interface between the RFIC (slave) and the host application (master) microcontroller
requires four signals:
SCLK – The serial data clock from the SPI master. Must be less than 8 MHz
MOSI – Serial data from the SPI master
MISO – Serial data from the SPI slave
RF_CS – Chip select from the SPI master
The SPI controller setting must be established by the host application microcontroller to be
compatible with the SPI interface timing specified by the RFIC data sheet.
5.0 SRF310 RF Characteristics
5.1 General RF Information
The RFIC used in the SRF310 RTM implements RF modulation modes and timings in
compliance with IEEE 802.15.4-2006. The RFIC implements additional proprietary RF
modulation modes. Details may be found in the AT86RF212B RFIC data sheet.
The SRF310 general spread spectrum scheme is DSSS. The modulation type is O-QPSK.
The data rate is 1000 kbps.
5.2 RF Exposure Considerations
The SRF310 RT module may be used in a variety of host applications that fall into two
general categories: mobile or portable. Mobile applications are any operating locations that are
not on a human body. Portable applications are those where the transmitting equipment is
located on the hand, arm or other part of the human body. In mobile applications the host
application is typically affixed to mobile equipment, with either an internal or external antenna. In
portable applications the equipment is typically held in the hand of an operator or affixed to
either a belt or harness on the torso.
Equipment containing the SRF310 RT module has been evaluated for RF exposure hazards
by two approaches: Maximum Permissible Exposure (MPE) for “mobile” applications and SAR
for portable applications. Mobile applications are any operating locations that are not on a
human body.