ATAM862 datasheet(14/110 Pages) ATMEL

14 / 110 page

4554E–4BMCU–05/06

ATAM862-3

14.1

Differences between ATAM862-3 and ATAR862 Microcontrollers

14.1.1

Program Memory

The program memory of the devices is realized as an EEPROM. The memory size for user pro-

grams is 4096 bytes. It is programmed as 258

× 16 bytes blocks of data. the implement

LOCK-bit function is user-selectable and protects the device from unauthorized read-out of the

program memory.

14.1.2

Configuration Memory

An additional area of 32 bytes of the EEPROM is used to store information about the hardware

configuration. All the options that are selectable for the ROM versions are available to the user.

This includes not only the different port options but also the possibilities to select different capac-

itors for OSC1 and OSC2, the option to enable or disable the hardlock for the watchdog, the

option to select OSC2 instead of OSC1 as external clock input and the option to enable the

external clock monitor as a reset source.

14.1.3

Data Memory

The microcontroller block contains an internal data EEPROM that is organized as two pages of

× 16-bit. To be compatible with the ROM parts, the page used has to be defined within the

application software by writing the 2-wire interface (TWI) command "09h" to the EEPROM. This

command has no effect for the microcontroller block, if it is left inside the HEX-file for the ROM

version. Also for compatibility reasons, the access to the EEPROM is handled via the MCL

(serial interface) as in the corresponding ROM parts.

14.1.4

Reset Function

During each reset (power-on or brown-out), the I/O configuration is deleted and reloaded with

the data from the configuration memory. This leads to a slightly different behavior compared to

the ROM versions. Both devices switch their I/Os to input during reset but the ROM part has the

mask selected pull-up or pull-down resistors active while the MTP has them removed until the

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