Datasheet

36
CC1350
SWRS183 –JUNE 2016 www.ti.com
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Detailed Description Copyright © 2016, Texas Instruments Incorporated
6.8 Clock Systems
The CC1350 supports two external and two internal clock sources.
A 24-MHz external crystal is required as the frequency reference for the radio. This signal is doubled
internally to create a 48-MHz clock.
The 32.768-kHz crystal is optional. The low-speed crystal oscillator is designed for use with a 32.768-kHz
watch-type crystal.
The internal high-speed RC oscillator (48-MHz) can be used as a clock source for the CPU subsystem.
The internal low-speed RC oscillator (32-kHz) can be used as a reference if the low-power crystal
oscillator is not used.
The 32-kHz clock source can be used as external clocking reference through GPIO.
6.9 General Peripherals and Modules
The I/O controller controls the digital I/O pins and contains multiplexer circuitry to assign a set of
peripherals to I/O pins in a flexible manner. All digital I/Os are interrupt and wake-up capable, have a
programmable pullup and pulldown function, and can generate an interrupt on a negative or positive edge
(configurable). When configured as an output, pins can function as either push-pull or open-drain. Five
GPIOs have high-drive capabilities, which are marked in bold in Section 4, Pin Diagram—RGZ Package.
The SSIs are synchronous serial interfaces that are compatible with SPI, MICROWIRE, and TI's
synchronous serial interfaces. The SSIs support both SPI master and slave up to 4 MHz.
The UART implements a universal asynchronous receiver and transmitter function. The UART supports
flexible baud-rate generation up to a maximum of 3 Mbps.
Timer 0 is a general-purpose timer module (GPTM) that provides two 16-bit timers. The GPTM can be
configured to operate as a single 32-bit timer, dual 16-bit timers, or as a PWM module.
Timer 1, Timer 2, and Timer 3 are also GPTMs. Each of these timers are functionally equivalent to Timer
0.
In addition to these four timers, the RF core has its own timer to handle timing for RF protocols; the RF
timer can be synchronized to the RTC.
The I
2
S interface is used to handle digital audio (see the CC13xx, CC26xx SimpleLink™ Wireless MCU
Technical Reference Manual for more information).
The I
2
C interface is used to communicate with devices compatible with the I
2
C standard. The I
2
C interface
can handle 100 kHz and 400 kHz operation, and can serve as both I
2
C master and I
2
C slave.
The TRNG module provides a true, nondeterministic noise source for the purpose of generating keys,
initialization vectors (IVs), and other random number requirements. The TRNG is built on 24 ring
oscillators that create unpredictable output to feed a complex nonlinear-combinatorial circuit.
The watchdog timer is used to regain control if the system fails due to a software error after an external
device fails to respond as expected. The watchdog timer can generate an interrupt or a reset when a
predefined time-out value is reached.