LM3S817 Datasheet, PDF (153/553 Pages) List of Unclassifed Manufacturers – Microcontroller

Stellaris^® LM3S817 Microcontroller
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 153 lists the external signals of the System Control module and describes 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 248) should be set to choose the NMI function. For more
information on configuring GPIOs, see “General-Purpose Input/Outputs (GPIOs)” on page 229. 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 (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 153)
■ Local control, such as reset (see “Reset Control” on page 153), power (see “Power
Control” on page 158) and clock control (see “Clock Control” on page 158)
5.2.1
5.2.2
5.2.2.1
■ System control (Run, Sleep, and Deep-Sleep modes); see “System Control” on page 161
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.
Reset Control
This section discusses aspects of hardware functions during reset as well as system software
requirements following the reset sequence.
Reset Sources
The controller has six sources of reset:
1. External reset input pin (RST) assertion; see “External RST Pin” on page 155.
July 14, 2014
153
Texas Instruments-Production Data