nRF24LE1 Nordic VLSI, nRF24LE1 Datasheet - Page 113

• Manufacturer Part Number: nRF24LE1
• Manufacturer: Nordic VLSI

nRF24LE1 Preliminary Product Specification
12.3.2
The Brown-Out Reset (BOR) generator puts the system in reset state if the supply voltage drops below the
BOR threshold. It consists of a high precision comparator that is enabled when the system is in active and
standby mode, and a less accurate low power comparator that is operational in all other modes. The for-
mer has a threshold voltage of about 1.8V. There is approximately 50mV of hysteresis (V
means that if a reset is triggered when the supply voltage drops below 1.8V, the supply must rise above
1.85V again before the nRF24LE1 becomes operational. Hysteresis prevents the comparator output from
oscillating when VDD is close to threshold. The low-power comparator has a typical threshold voltage of
1.5V.
12.3.3
The Power-Fail (POF) comparator provides the MCU with an early warning of impending power failure. It
will not reset the system, but gives the MCU time to prepare for an orderly power-down. It also provides
hardware protection of data stored in program memory, by preventing write instructions from being exe-
cuted.
The POF comparator is enabled or disabled by writing the enable bit in the POFCON register (see
65. on page
warn bit is set to ‘1’ if the supply voltage is below the programmable threshold. An interrupt (POFIRQ) is
also produced. Write instructions to program memory will not be executed as long as warn is ‘1’.
Revision 1.1
1.8V+V
1.9V
0V
114). When enabled, it will be powered up when the system is in active or standby mode. The
Brown-out reset
Power-fail comparator
1.8V
HYST
Voltage
X
Voltage
Figure 50. Brown-out reset
Figure 49. Power-on reset
>1ms
113 of 191
VDD
VDD
POR
BOR
HYST
). This
Time
Time
Table