LM3S101 Datasheet, PDF (132/445 Pages) List of Unclassifed Manufacturers – Microcontroller

System Control
5 System Control
System control determines the overall operation of the device. It provides information about the
device, controls the clocking to the core and individual peripherals, and handles reset detection and
reporting.
5.1 Signal Description
Table 5-1 on page 132 and Table 5-2 on page 132 list the external signals of the System Control
module and describe the function of each. The NMI signal is the alternate function for and functions
as a GPIO after reset. under commit protection and require a special process to be configured as
any alternate function or to subsequently return to the GPIO function. The column in the table below
titled "Pin Assignment" lists the GPIO pin placement for the NMI signal. The AFSEL bit in the GPIO
Alternate Function Select (GPIOAFSEL) register (page 219) should be set to choose the NMI
function. For more information on configuring GPIOs, see “General-Purpose Input/Outputs
(GPIOs)” on page 199. The remaining signals (with the word "fixed" in the Pin Assignment column)
have a fixed pin assignment and function.
Table 5-1. System Control & Clocks Signals (28SOIC)
Pin Name
Pin Number Pin Type Buffer Type^a Description
OSC0
9
I
Analog Main oscillator crystal input or an external clock reference
input.
OSC1
10
O
Analog Main oscillator crystal output. Leave unconnected when using
a single-ended clock source.
RST
5
I
TTL
System reset input.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
Table 5-2. System Control & Clocks Signals (48QFP)
Pin Name
Pin Number Pin Type Buffer Type^a Description
OSC0
9
I
Analog Main oscillator crystal input or an external clock reference
input.
OSC1
10
O
Analog Main oscillator crystal output. Leave unconnected when using
a single-ended clock source.
RST
5
I
TTL
System reset input.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
5.2 Functional Description
The System Control module provides the following capabilities:
■ Device identification (see “Device Identification” on page 132)
■ Local control, such as reset (see “Reset Control” on page 133), power (see “Power
Control” on page 137) and clock control (see “Clock Control” on page 137)
■ System control (Run, Sleep, and Deep-Sleep modes); see “System Control” on page 140
5.2.1
Device Identification
Several read-only registers provide software with information on the microcontroller, such as version,
part number, SRAM size, flash size, and other features. See the DID0, DID1, and DC0-DC4 registers.
132
July 14, 2014
Texas Instruments-Production Data