CC2533

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SWRS087 – JUNE 2010

A versatile five-channel DMA controller is available in the system, accesses memory using the XDATA memory

space, and thus has access to all physical memories. Each channel (trigger, priority, transfer mode, addressing

mode, source and destination pointers, and transfer count) is configured with DMA descriptors anywhere in

memory. Many of the hardware peripherals (AES core, flash controller, USARTs, timers, ADC interface) achieve

highly efficient operation by using the DMA controller for data transfers between SFR or XREG addresses and

flash/SRAM.

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 (the MAC Timer) is specially designed for supporting an IEEE 802.15.4 MAC or other time-slotted

protocol in software. The timer has 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, as well as two 16-bit output compare registers and two 24-bit overflow compare registers that can send

various command strobes (start RX, start TX, etc.) at specific times to the radio modules.

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 a PWM output.

The sleep timer is an ultralow-power timer that counts 32-kHz crystal oscillator or 32-kHz RC oscillator periods.

The sleep timer runs continuously in all operating modes except power mode 3 (PM3). Typical applications of

this timer are as a real-time counter or as a wake-up timer to come out of power mode 1 (PM1) or 2 (PM2).

The battery monitor comparator enables simple voltage monitoring in the devices that do not include an ADC. It

is designed such that it is accurate in the voltage areas around 2 V, with lower resolution at higher voltages.

The random-number generator uses a 16-bit LFSR to generate pseudorandom numbers, which can be read by

the CPU or used directly by the command strobe processor. It can be seeded with random data from noise in the

radio ADC.

The AES encryption/decryption core allows the user to encrypt and decrypt data using the AES algorithm with

128-bit keys. The core is able to support the security operations required by IEEE 802.15.4 MAC security, the

ZigBee network layer, and the application layer.

A built-in watchdog timer allows the CC2533 to reset itself in case the firmware hangs. When enabled by

software, the watchdog timer must be cleared periodically; otherwise, it resets the device when it times out. It can

alternatively be configured for use as a general 32-kHz timer.

USART 0 and USART 1 are each configurable as either a SPI master/slave or a UART. They provide double

buffering on both RX and TX, as well as hardware flow control, and are thus well suited to high-throughput

full-duplex applications. Each has its own high-precision baud-rate generator, thus leaving the ordinary timers

free for other uses.

operation.

Radio

The CC2533 features an IEEE 802.15.4-compliant radio transceiver. The RF core controls the analog radio

modules. In addition, it provides an interface between the MCU and the radio which makes it possible to issue

commands, read status, and automate and sequence radio events. The radio also includes a packet-filtering and

address-recognition module.

Copyright © 2010, Texas Instruments Incorporated

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