AX8052F151 datasheet(32/51 Pages) ONSEMI

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Circuit Description

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AX8052F151

The AX8052F151 contains an on-chip temperature sensor. Built-in calibration logic allows the

temperature sensor to be calibrated in °C, °F or any other user defined temperature scale.

The AX8052F151 also features two analog comparators. Each comparator can either compare two

voltages on dedicated PA pins, or one voltage against the internal 1V reference. The comparator

output can be routed to a dedicated digital output pin or can be read by software. The comparators

are clocked with the system clock.

5.6. DMA Controller

The AX8052F151 features a dual channel DMA engine. Each DMA channel can either transfer data

from XRAM to almost any peripheral on chip, or from almost any peripheral to XRAM. Both

channels may also be cross-linked for memory-memory transfers. The DMA channels use buffer

descriptors to find the buffers where data is to be retrieved or placed, thus enabling very flexible

buffering strategies.

The DMA channels access XRAM in a cycle steal fashion. They access XRAM whenever XRAM is not

used by the microcontroller. Their priority is lower than the microcontroller, thus interfering very

little with the microcontroller. Additional logic prevents starvation of the DMA controller.

5.7. AES Engine

The AX8052F151 contains a dedicated engine for the government mandated Advanced Encryption

Standard (AES). It features a dedicated DMA engine and reads input data as well as key stream

data from the XRAM, and writes output data into a programmable buffer in the XRAM. The round

number is programmable; the chip therefore supports AES-128, AES-192, and AES-256, as well as

higher security proprietary variants. Keystream (key expansion) is performed in software, adding

to the flexibility of the AES engine. ECB (electronic codebook), CFB (cipher feedback) and OFB

(output feedback) modes are directly supported without software intervention.

5.8. Crystal Oscillator (RF reference oscillator)

The on-chip crystal oscillator allows the use of an inexpensive quartz crystal as the RF generation

subsystem’s timing reference. Although a wider range of crystal frequencies can be handled by

the crystal oscillator circuit, it is recommended to use 16 MHz as reference frequency for ASK and

PSK modulations independent of the data rate. For FSK it is recommended to use a 16 MHz crystal

for data rates below 200 kbps and 24 MHz for data rates above 200 kbps.

The oscillator circuit is enabled by programming the transceiver

AX5051_PWRMODE register. At

power-up it is not enabled.

To adjust the circuit’s characteristics to the quartz crystal being used, without using additional

external components, both the transconductance and the tuning capacitance of the crystal

oscillator can be programmed.

The transconductance is programmed via register bits XTALOSCGM[3:0] in register

AX5051_XTALOSC.

AX8052F151 Datasheet(PDF) 32 Page - ON Semiconductor