TM4C1290NCPDT Datasheet, PDF (214/1628 Pages) Texas Instruments – Tiva Microcontroller

System Control
5 System Control
System control configures the overall operation of the device and provides information about the
device. Configurable features include reset control, NMI operation, power control, clock control, and
low-power modes.
5.1 Signal Description
The following table lists the external signals of the System Control module and describes the function
of each. The NMI signal is the alternate function for two GPIO signals, which default to GPIO after
reset. The NMI pins are under commit protection and require a special process to be configured as
any alternate function or to subsequently return to the GPIO function. See “Commit
Control” on page 730 for more information. The column in the table below titled "Pin Mux/Pin
Assignment" lists the GPIO pin placement for the NMI signal. The number in parentheses next to
the pin placement listed is the encoding that must be programmed into the PMCn field in the GPIO
Port Control (GPIOPCTL) register (page 765) to assign the NMI signal to the specified GPIO port
pin. In addition, the AFSEL bit in the GPIO Alternate Function Select (GPIOAFSEL) register
(page 748) should be set to choose the NMI function. For more information on configuring GPIOs,
see “General-Purpose Input/Outputs (GPIOs)” on page 719. The remaining signals listed in the table
(with the word "fixed" in the Pin Mux/Pin Assignment column) have a fixed pin assignment and
function.
Table 5-1. System Control & Clocks Signals (128TQFP)
Pin Name
DIVSCLK
NMI
OSC0
OSC1
RST
Pin Number Pin Mux / Pin
Assignment
102
PQ4 (7)
Pin Type
O
128
PD7 (8)
I
88
fixed
I
89
fixed
O
70
fixed
I
Buffer Type Description
TTL
TTL
Analog
Analog
TTL
An optionally divided reference clock output based
on a selected clock source. Note that this signal is
not synchronized to the System Clock.
Non-maskable interrupt.
Main oscillator crystal input or an external clock
reference input.
Main oscillator crystal output. Leave unconnected
when using a single-ended clock source.
System reset input.
5.2
5.2.1
Functional Description
The System Control module provides the following capabilities:
■ Device identification, see “Device Identification” on page 214
■ Configurable control of reset, power, and clock sources.
■ System control (Run, Sleep, and Deep-Sleep modes), see “System Control” on page 232
Device Identification
Read-only registers in the system control module provide information about the microcontroller,
such as version, part number, pin count, operating temperature range and available peripherals on
the device. The Device Identification 0 (DID0) (page 248) and Device Identification 1 (DID1)
(page 250) registers provide details about the device's version, package, temperature range, and so
on. The Peripheral Present registers starting at system control offset 0x300, such as the Watchdog
214
June 18, 2014
Texas Instruments-Production Data