LM3S101 Datasheet, PDF (135/445 Pages) List of Unclassifed Manufacturers – Microcontroller

Stellaris^® LM3S101 Microcontroller
Figure 5-2. External Circuitry to Extend Power-On Reset
VDD
Stellaris®
R_PU
RST
C₁
R_PU = 1 kΩ to 100 kΩ
C₁ = 1 nF to 10 µF
If the application requires the use of an external reset switch, Figure 5-3 on page 135 shows the
proper circuitry to use.
Figure 5-3. Reset Circuit Controlled by Switch
VDD
Stellaris®
R_PU
RST
R_S
C₁
5.2.2.4
Typical R_PU = 10 kΩ
Typical R_S = 470 Ω
C₁ = 10 nF
The R_PU and C₁ components define the power-on delay.
The external reset timing is shown in Figure 16-5 on page 410.
Brown-Out Reset (BOR)
A drop in the input voltage resulting in the assertion of the internal brown-out detector can be used
to reset the controller. This is initially disabled and may be enabled by software.
The system provides a brown-out detection circuit that triggers if the power supply (V_DD) drops
below a brown-out threshold voltage (V_BTH). The circuit is provided to guard against improper
operation of logic and peripherals that operate off the power supply voltage (V_DD) and not the LDO
voltage. If a brown-out condition is detected, the system may generate a controller interrupt or a
system reset. The BOR circuit has a digital filter that protects against noise-related detection for the
interrupt condition. This feature may be optionally enabled.
Brown-out resets are controlled with the Power-On and Brown-Out Reset Control (PBORCTL)
register. The BORIOR bit in the PBORCTL register must be set for a brown-out condition to trigger
a reset.
July 14, 2014
135
Texas Instruments-Production Data