Special pins

AN2353

12/18

There are two ways of disabling the BHE alternate function on P3.12:

–

–

Disable it via bit BYTDIS of the SYSCON register.

4

Special pins

4.1

External access enable/stand-by voltage supply pin

A low level applied to this pin during and after reset forces the ST10F27x to start the

program execution from the external memory space. A high level will start the program

execution from internal memory.

reference voltage for the low-power embedded voltage regulator which generates the

internal 1.8V supply for the XRTC module (when not disabled) and to retain data inside the

Stand-by portion of the XRAM (16 Kbyte). It can range from 4.5 to 5.5V.

4.2

RPD Pin

The RPD pin (Return from Power-Down) generates the proper internal timing sequence

when interruptible power-down mode is used.

If the interruptible power-down mode is not used, the RPD pin can be connected to the

ground (directly or via a resistor of 1M maximum). In this configuration, the device always

performs asynchronous resets.

For more details, please refer to application note AN2340,

ST10 RPD pin: Functionality

during Reset and Power-down mode.

5

Reset

For information on ST10F27x reset, please refer to the product user manual.