Rainbow Electronics AT86RF231 - Manual (Page 114)

114
8111A–AVR–05/08
AT86RF231
9.5.4 Interrupt Handling
A supply voltage drop below the configured threshold value is indicated by an interrupt IRQ_7
(BAT_LOW), see
Section 6.6 “Interrupt Logic” on page 29 . Note that the interrupt is issued only
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 observe the supply voltage at pin 28 (EVDD).
Additionally the supply voltage status at pin 28 (EVDD) is accessible 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 R R/W R/W R/W R/W R/W
Reset Value 0 0 0 0 0 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