CC2540T_15 Datasheet, PDF (24/37 Pages) Texas Instruments – SimpleLink CC2540T 2.4-GHz Bluetooth Low Energy Wireless MCU

CC2540T
SWRS172 – JULY 2014
www.ti.com
A built-in watchdog timer allows the CC2540T to reset itself if the firmware hangs. When enabled by
software, the watchdog timer must be cleared periodically; otherwise, it resets the device when it times
out.
Timer 1 is a 16-bit timer with timer/counter/PWM functionality. It has a programmable prescaler, a 16-bit
period value, and five individually programmable counter/capture channels, each with a 16-bit compare
value. Each of the counter/capture channels can be used as a PWM output or to capture the timing of
edges on input signals. It can also be configured in IR generation mode, where it counts timer 3 periods
and the output is ANDed with the output of timer 3 to generate modulated consumer IR signals with
minimal CPU interaction.
Timer 2 is a 40-bit timer used by the Bluetooth low energy stack. It has a 16-bit counter with a
configurable timer period and a 24-bit overflow counter that can be used to keep track of the number of
periods that have transpired. A 40-bit capture register is also used to record the exact time at which a
start-of-frame delimiter is received/transmitted or the exact time at which transmission ends. There are two
16-bit timer-compare registers and two 24-bit overflow-compare registers that can be used to give exact
timing for start of RX or TX to the radio or general interrupts.
Timer 3 and timer 4 are 8-bit timers with timer/counter/PWM functionality. They have a programmable
prescaler, an 8-bit period value, and one programmable counter channel with an 8-bit compare value.
Each of the counter channels can be used as PWM output.
USART 0 and USART 1 are each configurable as either an SPI master/slave or a UART. They provide
double buffering on both RX and TX and hardware flow control and are thus well suited to high-throughput
full-duplex applications. Each USART has its own high-precision baud-rate generator, thus leaving the
ordinary timers free for other uses. When configured as SPI slaves, the USARTs sample the input signal
using SCK directly instead of using some oversampling scheme, and are thus well-suited for high data
rates.
The AES encryption/decryption core allows the user to encrypt and decrypt data using the AES
algorithm with 128-bit keys. The AES core also supports ECB, CBC, CFB, OFB, CTR, and CBC-MAC, as
well as hardware support for CCM.
The ADC supports 7 to 12 bits of resolution with a corresponding range of bandwidths from 30-kHz to 4-
kHz, respectively. DC and audio conversions with up to eight input channels (I/O controller pins) are
possible. The inputs can be selected as single-ended or differential. The reference voltage can be internal,
AVDD, or a single-ended or differential external signal. The ADC also has a temperature-sensor input
channel. The ADC can automate the process of periodic sampling or conversion over a sequence of
channels.
The ultralow-power analog comparator enables applications to wake up from PM2 or PM3 based on an
analog signal. Both inputs are brought out to pins; the reference voltage must be provided externally. The
comparator output is connected to the I/O controller interrupt detector and can be treated by the MCU as a
regular I/O pin interrupt.
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Detailed Description
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