Page 29
RF65
Tel: +86-755-82973805 Fax: +86-755-82973550 E-mail: [email protected] http://www.hoperf.com
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
3.4.18. Temperature Sensor
When temperature is measured, the receiver ADC is used to digitize the sensor response. Most receiver blocks are
disabled, and temperature measurement can only be triggered in Standby or Frequency Synthesizer modes.
The response of the temperature sensor is -1°C / Lsb. A CMOS temperature sensor is not accurate by nature, therefore it
should be calibrated at ambient temperature for precise temperature readings.
TempValue
-1
°
C/Lsb
TempValue(t)
TempValue(t)-1
Returns 150d (typ.)
Needs calibration
-40
°
C
t t+1
Ambient
+85
°
C
Figure 13. Temperature Sensor Response
It takes less than 100 microseconds for the RF65 to evaluate the temperature (from setting
TempMeasStart
to 1 to
TempMeasRunning
reset).
3.4.19. Timeout Function
The RF65 includes a Timeout function, which allows it to automatically shut-down the receiver after a receive sequence
and therefore save energy.
Timeout interrupt is generated
TimeoutRxStart x 8 x Tbit
after switching to RX mode if
RssiThreshold
flag does not raise
within this time frame
Timeout interrupt is generated
TimeoutRssiThresh x 8 x Tbit
after
RssiThreshold
flag has been raised.
This timeout interrupt can be used to warn the companion processor to shut down the receiver and return to a lower power
mode.