Si1000/1/2/3/4/5
06h. Interrupt Enable 2.” The microcontroller will then need to verify the interrupt by reading the interrupt
status register, addresses 03 and 04h. The LSB step size for the LBD ADC is 50 mV, with the ADC range
demonstrated in the table below. If the LBD is enabled the LBD and ADC will automatically be enabled
every 1 s for approximately 250 µs to measure the voltage which minimizes the current consumption in
Sensor mode. Before an interrupt is activated four consecutive readings are required.
BatteryVoltage 1.7 50mV ADCValue
ADC Value
VDD Voltage [V]
< 1.7
0
1
1.7–1.75
1.75–1.8
…
2
…
29
30
31
3.1–3.15
3.15–3.2
> 3.2
23.8.6. Wake-Up Timer and 32 kHz Clock Source
The EZRadioPRO peripheral contains an integrated wake-up timer independent of the SmaRTClock which
can be used to periodically wake the chip from SLEEP mode using the interrupt pin. The wake-up timer
runs from the internal 32.768 kHz RC Oscillator. The wake-up timer can be configured to run when in
SLEEP mode. If enwt = 1 in "Register 07h. Operating Mode and Function Control 1" when entering SLEEP
mode, the wake-up timer will count for a time specified defined in Registers 14–16h, "Wake Up Timer
Period". At the expiration of this period an interrupt will be generated on the nIRQ pin if this interrupt is
enabled. The software will then need to verify the interrupt by reading the Registers 03h–04h, "Interrupt
Status 1 & 2". The wake-up timer value may be read at any time by the wtv[15:0] read only registers 17h–
18h.
The formula for calculating the Wake-Up Period is the following:
32 M 2R
WUT
ms
32.768
WUT Register
wtr[4:0]
Description
R Value in Formula
M Value in Formula
wtm[15:0]
Use of the D variable in the formula is only necessary if finer resolution is required than can be achieved by
using the R value.
Rev. 1.0
275
SILICON [ SILICON ]
