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8111C–MCU Wireless–09/09
AT86RF231
9.5.4
Interrupt Handling
A supply voltage drop below the configured threshold value is indicated by an interrupt IRQ_7
if BATMON_OK changes from 1 to 0.
No interrupt is generated when:
The battery voltage is under the default 1.8V threshold at power up
(BATMON_OK was never 1), or
A new threshold is set, which is still above the current supply voltage
(BATMON_OK remains 0).
When the battery voltage is close to the programmed threshold voltage, noise or temporary volt-
age drops may generate unwanted interrupts. To avoid this:
Disable the IRQ_7 (BAT_LOW) in register 0x0E (IRQ_MASK) and treat the battery as
empty, or
Set a lower threshold value.
9.5.5
Register Description
Register 0x11 (BATMON):
This register configures the battery monitor to compare the supply voltage at pin 28 (EVDD) to
the threshold BATMON_VTH. Additionally the supply voltage status at pin 28 (EVDD) is accessi-
ble by reading register bit BATMON_OK according to the actual BATMON settings.
Bit [7:6] - Reserved
Bit 5 - BATMON_OK
The register bit BATMON_OK indicates the level of the external supply voltage with respect to
the programmed threshold BATMON_VTH.
Bit 4 - BATMON_HR
BATMON_HR sets the range and resolution of the battery monitor.
Bit
7
6
5
4
3
2
1
0
+0x11
Reserved
BATMON_OK
BATMON_HR
BATMON_VTH
BATMON
Read/Write
R
R/W
Reset Value
0
1
0
Table 9-9.
Battery Monitor Status
Register Bit
Value
Description
BATMON_OK
0
The battery voltage is below the threshold.
1
The battery voltage is above the threshold.
Table 9-10.
Battery Monitor Range Selection
Register Bit
Value
Description
BATMON_HR
0
Enables the low range, see BATMON_VTH
1
Enables the high range, see BATMON_VTH