SAM3U datasheet(37/59 Pages) ATMEL

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6430ES–ATARM–22-Aug-11

SAM3U Series

10.1

System Controller and Peripheral Mapping

Please refer to Figure 8-1“SAM3U Memory Mapping” on page 30 .

All the peripherals are in the bit band region and are mapped in the bit band alias region.

10.2

Power-on-Reset, Brownout and Supply Monitor

The SAM3U embeds three features to monitor, warn and/or reset the chip:

• Power-on-Reset on VDDBU

• Brownout Detector on VDDCORE

• Supply Monitor on VDDUTMI

10.2.1

Power-on-Reset on VDDBU

The Power-on-Reset monitors VDDBU. It is always activated and monitors voltage at start up

but also during power down. If VDDBU goes below the threshold voltage, the entire chip is reset.

For more information, refer to the “Electrical Characteristics” section of the datasheet.

10.2.2

Brownout Detector on VDDCORE

The Brownout Detector monitors VDDCORE. It is active by default. It can be deactivated by soft-

ware through the Supply Controller (SUPC_MR). It is especially recommended to disable it

during low-power modes such as wait or sleep modes.

If VDDCORE goes below the threshold voltage, the reset of the core is asserted. For more infor-

mation, refer to the “Supply Controller” and “Electrical Characteristics” sections of the product

datasheet.

10.2.3

Supply Monitor on VDDUTMI

The Supply Monitor monitors VDDUTMI. It is not active by default. It can be activated by soft-

ware and is fully programmable with 16 steps for the threshold (between 1.9V to 3.4V). It is

controlled by the Supply Controller. A sample mode is possible. It allows to divide the supply

monitor power consumption by a factor of up to 2048. For more information, refer to the “Supply

Controller” and “Electrical Characteristics” sections of the product datasheet.

10.3

Reset Controller

The Reset Controller is capable to return to the software the source of the last reset, either a

general reset, a wake-up reset, a software reset, a user reset or a watchdog reset.

The Reset Controller controls the internal resets of the system and the NRST pin output. It is

capable to shape a reset signal for the external devices, simplifying to a minimum connection of

a push-button on the NRST pin to implement a manual reset.

10.4

Supply Controller

The Supply Controller controls the power supplies of each section of the processor and the

peripherals (via Voltage regulator control).

The Supply Controller has its own reset circuitry and is clocked by the 32 kHz Slow clock

generator.

The reset circuitry is based on a zero-power power-on reset cell. The zero-power power-on reset

allows the Supply Controller to start properly.

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